The Private Water Supplies (Scotland) Regulations 2006

Regulations 2(1), 7, 8, 17-26 and 28

SCHEDULE 1 S PRESCRIBED CONCENTRATIONS AND VALUES

Table A S Microbiological parameters

Part I: Directive requirements

(1)Item	(2)Parameters	(3)Concentration or Value (maximum)	(4)Units of Measurement
1.	Enterococci	0	number/100ml
2.	Escherichia coli (E. coli)	0	number/100ml

Part II: National requirements

(1)Item	(2)Parameters	(3)Concentration or Value (maximum)	(4)Units of Measurement
1.	Coliform bacteria	0	number/100ml

Table B S Chemical parameters

Part I: Directive requirements

(1)Item	(2)Parameters	(3)Concentration or Value (maximum)	(4)Units of Measurement
1.	Acrylamide(i)	0.10	µg/1
2.	Antimony	5.0	µgSb/l
3.	Arsenic	10	µgAs/l
4.	Benzene	1.0	µg/l
5.	Benzo(a)pyrene	0.010	µg/l
6.	Boron	1.0	mgB/l
7.	Bromate	10	µgBrO3/l
8.	Cadmium	5.0	µgCd/l
9.	Chromium	50	µgCr/l
10.	Copper	2.0	mg Cu/l
11.	Cyanide	50	µgCN/l
12.	1,2 dichloroethane	3.0	µg/l
13.	Epichlorohydrin(i)	0.10	µg/l
14.	Fluoride	1.5	mg F/l
15.	Lead	(a) 25, from 3/7/06 until 24/12/13	µgPb/l
		(b) 10, from 25/12/13	µgPb/l
16.	Mercury	1.0	µgHg/l
17.	Nickel	20	µgNi/l
18.	Nitrate	50	mgNO3/l
19.	Nitrite	0.50	mgNO2/l
20.	Pesticides(ii)–
	Aldrin	0.030	µg/l
	Dieldrin	0.030	µg/l
	Heptachlor	0.030	µg/l
	Heptachlor epoxide	0.030	µg/l
	other pesticides	0.10	µg/l
21.	Pesticides: Total(iii)	0.50	µg/l
22.	PAH(iv)	0.10	µg/l
23.	Selenium	10	µgSe/l
24.	Tetrachloroethene & Trichloroethene(v)	10	µg/l
25.	THM: Total(vi)	100	µg/l
26.	Vinyl chloride(i)	0.50	µg/l

Notes:

(i) The parametric value refers to the residual monomer concentration in the water as calculated according to specifications of the maximum release from the corresponding polymer in contact with the water. This is controlled by product specification.

(ii) See the definition of “pesticides and related products” in regulation 2(1). The parametric value applies to each individual pesticide.

(iii) “Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.

(iv) “PAH” means Polycyclic Aromatic Hydrocarbons, the specified compounds being:

• – benzo(b)fluoranthene

• – benzo(k)fluoranthene

• – benzo(ghi)perylene

• – indeno(1,2,3–cd)pyrene.

The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.

(v) The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.

(vi) “THM: Total” means total Trihalomethanes, the specified compounds being:

• – chloroform

• – bromoform

• – dibromochloromethane

• – bromodichloromethane.

The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.

Part II: National requirements

(1)Item	(2)Parameters	(3)Concentration or Value (maximum unless otherwise stated))	(4)Units of Measurement
1.	Aluminium	200	µgA1/1
2.	Colour	20	mg/l Pt/Co
3.	F1 . . .	F1 . . .	F1 . . .
4.	Iron	200	µgFe/l
5.	Manganese	50	µgMn/l
6.	F2 . . .	F2 . . .	F2 . . .
7.	Silver(i)	10	µg Ag/l
8.	Sodium	200	mgNa/l
9.	F3 . . .	F3 . . .	F3 . . .
10.	Tetrachloromethane	3	µg/l
11.	Turbidity(ii)	4	NTU
12.	Zinc	5000	µg Zn/l

Textual Amendments

F1 Sch. 1 Table B Pt. 2 entry omitted (28.11.2015) by virtue of The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(a)(i)

F2 Sch. 1 Table B Pt. 2 entry omitted (28.11.2015) by virtue of The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(a)(ii)

F3 Sch. 1 Table B Pt. 2 entry omitted (28.11.2015) by virtue of The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(a)(iii)

Notes:

(i) If Silver is used in a water treatment process, 80 may be substituted for 10.

(ii) Every effort should be made to achieve 1 NTU whenever possible.

Table C S Indicator parameters

Directive requirements

(1)Item	(2)Parameters	(3)Concentration or Value (maximum [F4 unless otherwise stated]) or State	(4)Units of Measurement
1.	Ammonium	0.50	mgNH4/l
2.	Chloride(i)	250	mgC1/1
3.	Clostridium perfringens (including spores)	0	Number/100 ml
4.	Coliform bacteria	0	Number/100 ml
5.	Colony count	No abnormal change	Number/1 ml at 22°C
[F5 5A	Colour	Acceptable to consumers and no abnormal change]
6.	Conductivity(i)	2500	µS/cm at 20°C
[F6 6A	Hydrogen ion	9.5 6.5 (minimum)	pH value]
[F6 6B	Odour	Acceptable to consumers and no abnormal change]
[F6 6C.	Radon (for radioactivity)(ii)	100	Bq/l]
7.	Sulphate(i)	250	mgSO4/l
[F7 7A	Taste	Acceptable to consumers and no abnormal change]
8.	Total indicative dose (for radioactivity)F8 ...	0.10	mSvF8 ...
9.	Total organic carbon (TOC)	No abnormal change	mgC/l
10.	Tritium (for radioactivity) [F9 (iii)]	100	Bq/l
[F10 10A	Turbidity	Acceptable to consumers and no abnormal change]

Textual Amendments

F4 Words in Sch. 1 Table C inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(b)(i)

F5 Sch. 1 Table C entry inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(b)(ii)

F6 Sch. 1 Table C entry inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(b)(iii)

F7 Sch. 1 Table C entry inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(b)(iv)

F8 Words in Sch. 1 Table C omitted (28.11.2015) by virtue of The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(b)(vi)

F9 Word in Sch. 1 Table C inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(b)(vii)

F10 Sch. 1 Table C entry inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(b)(v)

Notes:

(i) The water should not be aggressive.

[F11 (ii) Remedial action is to be deemed justified on radiological protection grounds, without further consideration, where radon concentrations exceed 1,000 Bq/l.

(iii) If the concentration of tritium exceeds this value, an analysis of the presence of other artificial radionuclides must be also carried out by Scottish Water.]

Textual Amendments

F11 Sch. 1 Table C Note (ii)(iii) substituted for Sch. 1 Table C Note (ii) (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 8(c)

Table D S Microbiological and Chemical Parameters: Type B Supplies

National Requirements

(1)Item	(2)Parameters	(3)Concentration or Value (maximum)	(4)Units of Measurement
1.	Coliform Bacteria	0	number/100ml
2.	Conductivity (i)	2500	µS/cm at 20°C
3.	Enterococci	0	number/100ml
4.	Escherichia coli (E.coli)	0	number/100ml
5.	Hydrogen ion	9.5 6.5 (minimum)	pH value
6.	Lead	(a) 25, from 3/7/06 until 24/12/13 (b) 10, from 25/12/13	µgPb/l
7.	Nitrate	50	mgNO3/l
8.	Odour-qualitative	-	-
9.	Taste-qualitative	-	-
10.	Turbidity	4	NTU

Notes:

(i) The water should not be aggressive.

Regulations 21-23, 29 and 30

SCHEDULE 2 S PARAMETERS, MONITORING AND SAMPLING FREQUENCIES

Table A S Check Monitoring: Type A Supplies

(1) Item	(2) Parameter	Annual sampling frequency(iv)(v)
		Volume of water distributed or produced each day within a supply zone (m3)(ii)(iii)
		(3)≤ 100Level 1	(4) > 100–≤ 1000Level 2	(5)> 1000Level 3(i)
1.	Aluminium (vi)	1	4(2)	X(X/2)
2.	Ammonium	1	4(2)	X(X/2)
3.	Clostridium perfringens (vii) (including spores)	1	4	X
4.	Coliform bacteria	1	4	X
5.	Colony counts	1	4	X
6.	Colour	1	4(2)	X(X/2)
7.	Conductivity	1	4(2)	X(X/2)
8.	Escherichia coli (E.coli)	1	4	X
9.	Hydrogen ion	1	(2)	X(X/2)
10.	Iron (vi)	1	4(2)	X(X/2)
11.	Nitrite (viii)	1	4(2)	X(X/2)
12.	Odour	1	4(2)	X(X/2)
13.	Taste	1	4(2)	X(X/2)
14.	Turbidity	1	4	X

Notes:

(i) The sampling frequency (X) shall be determined as X = 4 + (3 for each 1000 m3/d and part thereof of the total volume).

(ii) A supply zone is a geographically defined area within which water intended for human consumption comes from one or more sources and within which water quality may be considered as being approximately uniform.

(iii) The volumes are calculated as averages taken over a calendar year or using consumption based on the number of inhabitants, assuming a water consumption rate of 200 l/day/capita.

(iv) Values in (brackets) in columns (4) and (5) are reduced sampling frequencies which may be applied if–

(aa) the values of the results obtained from samples taken during a period of at least two successive years are constant and significantly better than the limits laid down in Schedule 1; and

(bb) no factor is likely to cause a deterioration of the quality of the water.

(v) As far as possible, the number of samples should be distributed equally in time and location and should be representative of the quality of water consumed or available for consumption throughout the year.

(vi) Necessary only when used as a flocculant. In all other cases the parameter will be sampled according to the frequency specified for audit monitoring (Table B of Schedule 2).

(vii) Necessary only if the water originates from, or is influenced by, surface water. In all other cases the parameter will be sampled according to the frequency specified for audit monitoring (Table B of Schedule 2).

(viii) Necessary only when chloramination is used as a disinfectant. In all other cases the parameter will be sampled according to the frequency specified for audit monitoring (Table B of Schedule 2).

Table B S Audit Monitoring: Type A Supplies

		Annual sampling frequency
		Volume of water distributed or produced each day within a supply zone (m3)(ii)(iii)
(1)Item	(2)Parameters	(3) ≤ 100Level 1	(4)> 100 – ≤ 1000Level 2	(5)> 1000Level 3(i)
1.	Acrylamide	1	1	Y
2.	Aluminium	1	1	Y
3.	Antimony	1	1	Y
4.	Arsenic	1	1	Y
5.	Benzene	1	1	Y
6.	Benzo(a)pyrene	1	1	Y
7.	Boron	1	1	Y
8.	Bromate	1	1	Y
9.	Cadmium	1	1	Y
10.	Chloride	1	1	Y
11.	Chromium	1	1	Y
12.	Clostridium perfringens (including spores)	1	1	Y
13.	Copper	1	1	Y
14.	Cyanide	1	1	Y
15.	1,2 dichloroethane	1	1	Y
16.	Enterococci	1	1	Y
17.	Epichlorohydrin	1	1	Y
18.	Fluoride	1	1	Y
19.	Iron	1	1	Y
20.	Lead	1	1	Y
21.	Manganese	1	1	Y
22.	Mercury	1	1	Y
23.	Nickel	1	1	Y
24.	Nitrate	1	1	Y
25.	Nitrite	1	1	Y
26.	Pesticides	1	1	Y
27.	Pesticides – Total	1	1	Y
28.	Polycyclic Aromatic Hydrocarbons	1	1	Y
[F12 28A	Radon	1	1	Y]
29.	Selenium	1	1	Y
30.	Silver	1	1	Y
31.	Sodium	1	1	Y
32.	Sulphate	1	1	Y
33.	Tetrachloroethene and Trichloroethene	1	1	Y
34.	Tetrachloromethane	1	1	Y
35.	Total indicative dose	1	1	Y
36.	Total organic carbon	1	1	Y
37.	Trihalomethanes – Total	1	1	Y
38.	Tritium	1	1	Y
39.	Vinyl chloride	1	1	Y
40.	Zinc	1	1	Y

Textual Amendments

F12 Words in Sch. 2 Table B inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 9

Notes:

(i) The sampling frequency (Y) shall be determined by–

Volume of water supplied each day (m3)	Y
> 1000 – �?� 10,000	1 + (1 for each 3,300 m3/d and part thereof of total volume)
> 10,000 – �?� 100,000	3 + (1 for each 10,000 m3/d and part thereof of total volume)
> 100,000	10 + (1 for each 25,000 m3/d and part thereof of total volume)

Table C S Routine Monitoring: Type B Supplies

Parameters

1.  Coliform bacteria S

2.  Conductivity S

3.  Enterococci S

4.  Escherichia coli (E. coli) S

5.  Hydrogen ion S

6.  Lead S

7.  Nitrate(i) S

8.  Odour – qualitative(ii) S

9.  Taste – qualitative(ii) S

10.  Turbidity S

Notes:

(i) Samples need not be analysed for nitrate if there are reasonable grounds for believing that nitrate levels in the locality concerned are below 25 mg NO3/l.

(ii) Samples should not be assessed qualitatively if there are reasonable grounds for suspecting that the water may give rise to a health hazard.

Regulation 21(2A)

[F13 SCHEDULE 2A S MONITORING OF RADIOACTIVE SUBSTANCES

Textual Amendments

F13 Sch. 2A inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 10

General principles and monitoring frequencies S

1.— (1) Subject to sub-paragraphs (2) and (3), the monitoring local authority must monitor Type A supplies, which serve premises located in the area of the authority, for—

(a) radon (item 6C) in Table C of Schedule 1;

(b) total indicative dose (item 8) in that table; and

(c) tritium (item 10) in that table.

(2) Where the Scottish Ministers, by notice in writing to the monitoring local authority, confirm that they have established that radon, total indicative dose or, as the case may be, tritium (“the parameter”) is not likely to be present, for a period specified in the notice, in a Type A supply (which serves premises located in the area of the authority) in concentrations which could exceed the prescribed concentration or value for that parameter, the monitoring local authority is not required to monitor the supply for the parameter during the period specified in the notice.

(3) In case of naturally occurring radionuclides—

(a) where previous results show that the concentration of radionuclides in the supply is stable, the minimum sampling and analysis frequencies are to be decided by the Scottish Ministers, and confirmed by notice in writing to the monitoring local authority, taking into consideration the risk to human health; and

(b) where the Scottish Ministers, by notice in writing to the monitoring local authority, confirm that they are satisfied (on the basis of representative surveys, monitoring data or other reliable information) that levels of radon, tritium and the calculated total indicative dose in a Type A supply (which serves premises located in the area of the monitoring local authority) will, for a period specified in the notice, remain below the prescribed concentration or value for each parameter, the monitoring local authority is not required to monitor the supply for these parameters during the period specified in the notice.

(4) Where sub-paragraph (3)(b) applies, the Scottish Ministers must communicate the grounds for the decision to the European Commission and provide the Commission with the necessary documentation supporting that decision, including the findings of any surveys, monitoring or investigations carried out.

Radon S

2.— (1) Subject to paragraphs 5 and 6, the monitoring local authority must ensure that representative surveys are undertaken to determine the scale and nature of likely exposures to radon in Type A supplies (which serve premises located in the area of the authority) originating from different types of groundwater sources and wells in different geological areas.

(2) The surveys must be designed in such a way that underlying factors, and especially the geology and hydrology of the area, radioactivity of rock or soil, and well type, can be identified and used to direct further action to areas of likely high exposure.

(3) Monitoring of radon concentrations must be carried out if the monitoring local authority has reason to believe, on the basis of the results of the representative surveys or other reliable information, that the prescribed concentration or value for radon might be exceeded.

Tritium S

3.— (1) Subject to paragraphs 5 and 6, the monitoring local authority must monitor Type A supplies (which serve premises located in the area of the authority) for tritium where—

(a) an anthropogenic source of tritium or other artificial radionuclides is present within the catchment area for the supply; and

(b) it cannot be shown on the basis of other surveillance programmes or investigations that the level of tritium is below the prescribed concentration or value for tritium.

(2) Where monitoring for tritium is required by sub-paragraph (1), samples must be taken in accordance with regulation 23(1) (as read with regulation 22).

(3) If the concentration of tritium in any such sample exceeds the prescribed concentration or value for tritium, the monitoring local authority must carry out an investigation of the presence of other artificial radionuclides.

Total indicative dose S

4.— (1) Subject to paragraphs 5 and 6, the monitoring local authority must monitor Type A supplies (which serve premises located in the area of the authority) for total indicative dose where—

(a) a source of artificial radioactivity or elevated natural radioactivity is present; and

(b) it cannot be shown on the basis of other representative monitoring programmes or other investigations that the level of total indicative dose is below the prescribed concentration or value for that parameter.

(2) Where sub-paragraph (1) requires monitoring (of radionuclide levels) only in relation to a source of artificial radioactivity, samples must be taken in accordance with regulation 23(1) (as read with regulation 22).

(3) Where sub-paragraph (1) requires monitoring (of radionuclide levels) in relation to a source of elevated natural radioactivity, the Scottish Ministers must specify, by notice in writing to the monitoring local authority, the frequency of the monitoring required of—

(a) gross alpha activity;

(b) gross beta activity; or

(c) individual natural radionuclides,

for screening strategies pursuant to regulation 21(2A)(b) and Schedule 5A.

(4) Where sub-paragraph (3) applies, the frequency specified may vary from a single check measurement to the frequency which would otherwise apply under regulation 23(1).

(5) Where a single check for natural radioactivity is specified under sub-paragraph (3), the monitoring local authority must carry out a further check if any change occurs in relation to the supply which is likely to influence the concentrations of radionuclides in the supply.

Water treatment S

5.   Where a Type A supply (which serves premises located in the area of a monitoring local authority) is treated to reduce the level of radionuclides, the monitoring local authority must monitor the supply for total indicative dose, radon and tritium in accordance with regulation 23(1) (as read with regulation 22) to verify the continued efficacy of that treatment.

Averaging S

6.   In circumstances where the prescribed concentration or value for total indicative dose, radon or, as the case may be, tritium is exceeded in a sample taken in relation to a Type A supply (which serves premises located in the area of a monitoring local authority), the Scottish Ministers must specify, by notice in writing to the monitoring local authority, the extent of resampling necessary to ensure that the measured values are representative of an average activity concentration for a full year.]

Regulation 26

SCHEDULE 3 S CIRCUMSTANCES AND CONDITIONS TO BE CONSIDERED BY A MONITORING LOCAL AUTHORITY: DECISION ON AUDIT MONITORING

(1) Where a monitoring local authority carries out an investigation in relation to a Type A supply for the purposes of regulation 26, it shall do so in accordance with the provisions of this Schedule and shall take into account the matters specified in Schedule 4.

(2) Where a monitoring local authority considers that one or more of the parameters listed in the Table in this Schedule is not likely to be present in a Type A supply in its area in concentrations which could lead to the risk of a breach of the parametric value in respect of the parameters specified in Table B of Schedule 2, it shall undertake such investigations as are considers reasonable to satisfy itself–

(a) that the circumstances referred to in column 3 of the Table in this Schedule in respect of that parameter do not exist; and

(b) whether any of the conditions referred to in column 4 of the Table in this Schedule in respect of that parameter, apply.

(3) Where a monitoring local authority is satisfied, as a result of its investigations under paragraph (2), that in respect of the supply, one or more of the parameters referred to in column 2 of the Table in this Schedule is not likely to be present in that supply in concentrations which could lead to the risk of a breach of the said parametric value in respect of such parameters, it may make a decision in accordance with regulation 26.

Table

(1)Item No.	(2)Parameter	(3)Circumstances in which parameter is likely to be present	(4)Conditions to be satisfied before a decision may be made
(1)	Acrylamide	Residual acrylamide monomer occurs in polyacrylamide coagulants used in drinking water treatment.   May also be used as grouting agents (polyacrylamide) in wells/borehole linings.	Coagulation is not practised.   Grouting agents are present but that they do not have an acrylamide content.
(2)	Aluminium	Aluminium salts are widely used in water treatment as coagulants to reduce organic matter, colour, turbidity and micro organism levels.	Coagulation is not practised.
(3)	Antimony	Most common source of antinomy in drinking water appears to be dissolution from metal plumbing fittings.	If the monitoring local authority is satisfied that antimony is not present at or above 75% of PCV then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(4)	Arsenic	Arsenic is introduced into drinking water sources primarily through the dissolution of naturally occurring minerals and ores.   Arsenic in drinking water is a significant source of health effects in some areas.   Arsenic is considered to be a high-priority substance for screening in drinking water sources.   Concentrations are highly dependent on the depth to which a well or borehole is sunk.	If the monitoring local authority is satisfied that arsenic is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(5)	Benzene	Benzene is used principally in the production of other organic chemicals.   As benzene is present in petrol, vehicular emissions constitute the main source of the chemical in the environment.   Benzene may be introduced into water by industrial effluents and atmospheric pollution.	Where the source of the supply comprises groundwater (well, spring, borehole or similar) the area in which the source is located must be an area devoid of industrial activity (current or historic) or hydrocarbon stores (current or historic) eg, underground petroleum tanks.   Where the source of the supply comprises surface water, the area in which the source is located must be an area remote from areas of industrial activity (current or historic) or remote from areas of high vehicular activity.
(6)	Benzo(a)pyrene	See PAH	See PAH
(7)	Boron	Boron is found naturally in groundwater but its presence in surface water is frequently a consequence of the discharge of treated sewage effluent, in which it arises from its use in detergents, to surface water.	If the monitoring local authority is satisfied that Boron is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(8)	Bromate	Bromate is not normally found in water but may be formed during ozonation when the bromide ion is present in water.	No ozonation or chlorination to be undertaken on the supply.
		Under certain conditions bromate may also be found in concentrated hypochlorite solutions used to disinfect drinking water including electrolytic production of chlorine from sodium chloride
(9)	Cadmium	Cadmium is released into the environment in wastewater.   Diffuse pollution is also caused by contamination from fertilizers and local air pollution.   Contamination in drinking water may also be caused by impurities in the zinc of galvanised pipes and solders and some metal fittings.	If the monitoring local authority is satisfied that Cadmium is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(10)	Chromium	Chromium is widely distributed in the Earth's crust. Soils and rocks may contain small amounts.	If the monitoring local authority is satisfied that Chromium is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(11)	Copper	Copper concentrations in drinking water vary widely with the primary source most often being the corrosion of interior copper plumbing.   Copper concentrations in treated water often increase during distribution, especially in systems with an acid pH or high carbonate waters with an alkaline pH.   Consumption of standing or partially flushed water from a distribution system that includes copper pipes or fittings can considerably increase total daily copper exposure, especially for infants fed formula reconstituted with tap water.	If the monitoring local authority is satisfied that Copper is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(12)	Cyanide	Cyanides are occasionally found in drinking water primarily as a consequence of industrial contamination.	If the monitoring local authority is satisfied that Cyanide is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(13)	1,2 dichloroethane	1,2 dichloroethane is used mainly as an intermediate in the production of vinyl chloride and other chemicals and to a lesser extent as a solvent.   It may enter surface waters via effluents from industries that manufacture or use the substance.   It may also enter groundwater, where it persists for long periods, following disposal in waste sites.	If the monitoring local authority is satisfied that 1,2 dichloroethane is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(14)	Epichlorohydrin	Epichlorohydrin is used for the manufacture of glycerol, unmodified epoxy resins and water treatment resins.   It is also found in some polyamine flocculants.	Coagulation is not practiced using polyamine flocculants.   If ion exchange resins are present in the system then it should be sampled for against the prescribed frequency specified in Schedule 2.
(15)	Fluoride	Fluoride is present in a number of minerals.   Fluoride may also be present in phosphate fertilizers.	If the monitoring local authority is satisfied that Fluoride is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(16)	Iron	Iron is found in natural fresh waters.   Iron may also be present in drinking water as a result of iron coagulants or the corrosion of steel and cast iron pipes during water distribution.	If the monitoring local authority is satisfied that Iron is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(17)	Lead	Lead is rarely present in tap water as a result of its dissolution from natural sources.   The presence of lead is primarily from household plumbing systems containing lead in pipes, solder, fittings or the service connections to homes.	If the monitoring local authority is satisfied that Lead is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(18)	Manganese	Manganese is naturally occurring in many surface and groundwater sources, particularly in anaerobic or low oxidation conditions.   Manganese greensands are used in some locations for potable water treatment.	If the monitoring local authority is satisfied that Manganese is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(19)	Mercury	Mercury can be used in the electrolytic production of chlorine.	If electrolytic production of chlorine is used as part of the treatment process the supply should be sampled as specified in Schedule 2;
			if electrolytic production of chlorine is not used as part of the treatment process, and if the monitoring local authority is satisfied that mercury is not present at or above 75% of PCV, then an exemption under regulation 26 may be granted, otherwise it should be sampled for at the frequency specified in Schedule 2.
(20)	Nickel	Nickel may be present as a result of plumbing fittings eg from nickel- or chromium-plated taps.	If the monitoring local authority is satisfied that Nickel is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(21)	Nitrate	Nitrate is used mainly in inorganic fertilisers. The nitrate concentration in groundwater and surface water is normally low but can reach high levels as a result of leaching or runoff from agricultural land or contamination from human or animal wastes as a consequence of oxidation of ammonia or similar sources.	If the supply is in an area where agricultural fertilisers are used then the supply should be sampled as specified in Schedule 2;   if the supply is in an area where agricultural fertilisers are not used, and if the monitoring local authority is satisfied that nitrate is not present at or above 75% of PCV, then an exemption under regulation 26 may be granted, otherwise it should be sampled for at the frequency specified in Schedule 2.
(22)	Nitrite	Nitrite is formed during the decomposition of organic matter but high concentrations are usually associated with poor control of chloramination or chlorine disinfection of water containing significant amounts of ammonium ions.	If the monitoring local authority is satisfied that Nitrite is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(24)	Pesticides	See definition of “pesticides and related products” in regulation 2(1).   The range of pesticides and related products that may be being used in any one area should be assessed on an individual supply basis.	If the monitoring local authority is satisfied that Pesticides are not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise they should be sampled for at the frequency specified in Schedule 2.
(25)	Pesticides – Total	“ Pesticides – Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.	See Pesticides.
(26)	Polycyclic Aromatic Hydrocarbons (PAH)	The main source of PAH contamination in drinking water is usually the coal-tar coating of drinking water distribution pipes used to protect the pipes from corrosion.	If the monitoring local authority is satisfied that PAH are not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise they should be sampled for at the frequency specified in Schedule 2.
[F14 (26A)	Radon	The supply is located in an area which puts it at high risk of exceeding the prescribed concentration or value for radon (at the point referred to in regulation 7(5)) and the supply is not open to atmospheric pressure before that point.	The monitoring local authority for the supply in question is in receipt of a notice under regulation 24(1) which specifies, for an area in which that supply is located, that the condition in regulation 24(2)(za) is satisfied (and the notice applies to that extent).]
(27)	Selenium	Selenium is present in the Earth's crust, often in association with sulphur-containing minerals and hence the concentration in drinking water will vary with local geology and geography.	If the monitoring local authority is satisfied that Selenium is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(28)	Silver	Silver may be used in some water treatment devices where it is used for disinfection purposes.	If the monitoring local authority is satisfied that Silver is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(29)	Sodium	Concentrations in potable water are typically low but some water softeners can add significantly to the sodium content of drinking water.	If the monitoring local authority is satisfied that Sodium is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(30)	Sulphate	Sulphates occur naturally in numerous minerals and are used commercially but the highest levels found in groundwaters are from natural sources.   Sulphates may occur in surface waters that have received industrial discharges.	If the monitoring local authority is satisfied that Sulphate is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(31)	Tetrachloroethene and Trichloroethene	These chemicals are used primarily as solvents in dry cleaning industries and as degreasing solvents.	If the monitoring local authority is satisfied that Tetrachloroethene and Trichloroethene are not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise they should be sampled for at the frequency specified in Schedule 2.
(32)	Tetrachloromethane	Chlorinated organic compound (also known as carbon tetrachloride) that is a very efficient solvent for fats and greases, and was at one time the main constituent of household dry-cleaning fluids and of fire extinguishers used with electrical and petrol fires.	If the monitoring local authority is satisfied that Tetrachloromethane is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(33)	Total indicative dose	Routine monitoring [F15 of the supply indicates that the total indicative dose is not likely to be well below the prescribed concentration or value for that parameter.]	[F16 The monitoring local authority for the supply in question is in receipt of a notice under regulation 24(1) which specifies, for an area in which that supply is located, that the condition in regulation 24(2)(a) is satisfied (and the notice applies to that extent)]
(34)	Trihalomethanes – Total	These compounds are generated principally as by-products of the chlorination of drinking water, being formed from naturally occurring organic compounds.	No chlorination is undertaken on the supply.
(35)	Tritium	[F17 Routine monitoring of the supply indicates that tritium is not likely to be well below the prescribed concentration or value for that parameter.]	[F18 The monitoring local authority for the supply in question is in receipt of a notice under regulation 24(1) which specifies, for an area in which that supply is located, that the condition in regulation 24(2)(b) is satisfied (and the notice applies to that extent).]
(36)	Vinyl chloride	Vinyl chloride is used primarily for the production of PVC.   When unplasticised PVC is in contact with water it is possible for the vinyl chloride monomer to be released into the water.   Unplasticised PVC pipes should not be used for drinking water supplies. This is controlled by product specification.	Unplasticised PVC pipes not present.   If the monitoring local authority is satisfied that Vinyl chloride is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.
(37)	Zinc	Traces of zinc occur naturally in many water sources but significant concentrations may occur as a consequence of the use of brass fittings and galvanised iron pipes.	If the monitoring local authority is satisfied that Zinc is not present at or above 75% of PCV, then an exemption may be granted under regulation 26, otherwise it should be sampled for at the frequency specified in Schedule 2.

Textual Amendments

F14 Sch. 3 Table entry inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 11(a)

F15 Words in Sch. 3 Table substituted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 11(b)(i)

F16 Words in Sch. 3 Table substituted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 11(b)(ii)

F17 Words in Sch. 3 Table substituted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 11(c)(i)

F18 Words in Sch. 3 substituted Table (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 11(c)(ii)

Regulations 16 and 26 and 27

SCHEDULE 4 S REQUIREMENTS FOR RISK ASSESSMENT

(1) When undertaking or reviewing and updating a risk assessment for the purposes of regulations 16 and 27, a monitoring local authority shall do so in accordance with the provisions of this Schedule.

(2) A risk assessment shall comprise the following–

(a) documentation on and a description of the private water supply, including the catchment from which the supply draws water;

(b) a hazard assessment and risk characterisation;

(c) an identification of the measures by which risks may be controlled; and

(d) establishment of verification procedures,

and for the purposes of this paragraph, “hazard” means a biological, chemical, physical or radiological agent that has the potential to cause harm or danger to human health; and “risk” means the likelihood of identified hazards causing harm in exposed populations in a specified time, including the magnitude of that harm and/or the consequences of such harm.

(3) In respect of a private water supply which comprises, either alone or in any combination thereof, catchments, surface water or ground water, the risk assessment shall include provision in relation to the relevant matters specified in Table A of this Schedule.

(4) In respect of a private water supply which receives treatment, including treatment at source and at any point thereafter, the risk assessment shall make provision in relation to the relevant matters specified in Table B of this Schedule.

(5) In respect of a private water supply which comprises intermediate tanks and distribution, the risk assessment shall include provision in relation to the relevant matters specified in Table C of this Schedule.

Table A

Hazard Information and Risk Characterisation

(1)Source of private water supply	(2)Information to be considered in the risk assessment
(1) Catchments	(i) geology and hydrology
	(ii) meteorology and weather patterns
	(iii) general catchment and river health
	(iv) wildlife
	(v) competing water uses
	(vi) nature and intensity of development and land use
	(vii) other activities in the catchment that potentially release contaminants into source water
	(viii) planned future activities
(2) Surface water	(i) description of water body type (e.g. river, reservoir, dam)
	(ii) flow and reliability of source water
	(iii) retention times
	(iv) water constituents (physical, chemical, microbial)
	(v) protection (e.g. enclosures, access)
	(vi) recreational and other human activity
	(vii) bulk water transport
(3) Groundwater	(i) confined or unconfined aquifer
	(ii) aquifer hydrogeology
	(iii) flow rate and direction
	(iv) dilution characteristics
	(v) recharge area
	(vi) wellhead protection
	(vii) depth of casing
	(viii) bulk water transport

Table B

Treatment: Hazard Identification and Risk Characterisation

(i) treatment processes

(ii) equipment design

(iii) monitoring equipment and automation

(iv) water treatment chemicals used

(v) treatment efficiencies

(vi) disinfection removals of pathogens

(vii) disinfection residuals/contact time

Table C

Intermediate Tanks and Distribution: Hazard Identification and Risk Characterisation

(i) reservoir/tank design

(ii) retention times

(iii) seasonal variations

(iv) protection (e.g. covers, enclosures, access)

(v) distribution system design

(vi) hydraulic conditions (e.g. water age, pressures, flows)

(vii) backflow protection

(viii) disinfectant residuals

Regulations 22, 29 and 31

SCHEDULE 5 S ANALYTICAL METHODOLOGY

Table A

Parameters for which, subject to regulation 31(4), methods of analysis are prescribed

(1)Parameter	(2)Method
Clostridium perfringens (including spores)	Membrane filtration followed by anaerobic incubation of the membrane on m–CP agar(i) at 44 ± 1°C for 21 ± 3 hours. Count opaque yellow colonies that turn pink or red after exposure to ammonium hydroxide vapours for 20 to 30 seconds.
Coliform bacteria	ISO 9308–1
Colony count 22°C – enumeration of culturable micro-organisms	prEN ISO 6222
Enterococci	ISO 7899–2
Escherichia coli (E.coli)	ISO 9308–1

(i) The composition of m–CP agar is:

• Basal medium

  Tryptose	30g
  Yeast extract	20g
  Sucrose	5g
  L–cysteine	1g
  MgSO4 . 7H2O	0.1g
  Bromocresol purple	40mg
  Agar	15g
  Water	1,000ml

• Dissolve the ingredients of the basal medium, adjust pH to 7.6 and autoclave at 121°C for 15 minutes. Allow the medium to cool and add:

  D–cycloserine	400mg
  Polymyxine–B–sulphate	25mg
  Indoxyl–β-D-glucoside to be dissolved in 8ml sterile water before addition	60mg
  Filter – sterilised 0.5% phenolphthalein disphosphate solution	20ml
  Filter – sterilised 4.5% FeC13 . 6H2O	2ml

Table B

Parameters in relation to which methods of analysis must satisfy prescribed characteristics

(1)Item No.	(2)Parameters	(3)Trueness % of prescribed concentration or value or specification	(4)Precision % of prescribed concentration or value or specification	(5)Limit of detection % of prescribed concentration or value or specification
1.	Aluminium	10	10	10
2.	Ammonium	10	10	10
3.	Antimony	25	25	25
4.	Arsenic	10	10	10
5.	Benzene	25	25	25
6.	Benzo(a)pyrene	25	25	25
7.	Boron	10	10	10
8.	Bromate	25	25	25
9.	Cadmium	10	10	10
10.	Chloride	10	10	10
11.	Chromium	10	10	10
12.	Colour	10	10	10
13.	Conductivity	10	10	10
14.	Copper	10	10	10
15.	Cyanide(i)	10	10	10
16.	1,2–dichloroethane	25	25	25
17.	Fluoride	10	10	10
18.	Iron	10	10	10
19.	Lead	10	10	10
20.	Manganese	10	10	10
21.	Mercury	20	10	20
22.	Nickel	10	10	10
23.	Nitrate	10	10	10
24.	Nitrite	10	10	10
25.	Pesticides and related products(ii)	25	25	25
26.	Polycyclic aromatic hydrocarbons(iii)	25	25	25
27.	Selenium	10	10	10
28.	Sodium	10	10	10
29.	Sulphate	10	10	10
30.	Tetrachloroethene(iv)	25	25	10
31.	Tetrachloromethane	20	20	20
32.	Trichloroethene(iv)	25	25	10
33.	Trihalomethanes:Total(iii)	25	25	10
34.	Turbidity(v)	10	10	10

Notes:

(ii) The method of analysis should determine total cyanide in all forms.

(iii) The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned.

(iv) The performance characteristics apply to the individual substances specified at 25% of the parametric value in Table B in Schedule 1.

(v) The performance characteristics apply to the individual substances specified at 50% of the parametric value in Table B in Schedule 1.

(vi) The performance characteristics apply to the prescribed value of 4NTU.

Regulation 21(2A)

[F19 SCHEDULE 5A S MONITORING FOR TOTAL INDICATIVE DOSE AND ANALYTICAL PERFORMANCE CHARACTERISTICS

Textual Amendments

F19 Sch. 5A inserted (28.11.2015) by The Private and Public Water Supplies (Miscellaneous Amendments) (Scotland) Regulations 2015 (S.S.I. 2015/346), regs. 1(1), 12

Monitoring for compliance with the total indicative dose S

1.— (1) The monitoring local authority may use reliable screening strategies to indicate the presence of radioactivity in Type A supplies (which serve premises located in the area of the authority).

(2) These strategies may include screening for—

(a) certain radionuclides or an individual radionuclide; or

(b) gross alpha activity or gross beta activity.

Screening for certain radionuclides or for an individual radionuclide S

2.— (1) Where screening is carried out for certain radionuclides or for an individual radionuclide, the monitoring local authority must carry out an analysis of additional radionuclides if, in relation to any supply referred to in paragraph 1—

(a) one of the activity concentrations of a radionuclide listed in column 2 of the table below exceeds 20% of the corresponding derived concentration in column 3; or

(b) the tritium concentration exceeds the prescribed concentration or value for tritium.

(2) The monitoring local authority must, in deciding which radionuclides require to be measured for each supply, take into account all relevant information about likely sources of radioactivity.

1 This table includes values for the most common natural and artificial radionuclides. These are precise values, calculated for a dose of 0.1 mSv, an annual intake of 730 litres and using the dose coefficients laid down in Table (A) of Annex III to Council Directive 96/29/Euratom laying down basic safety standards for the protection of the health of workers and the general public against the dangers arising from ionizing radiation F20 . Derived concentrations for other radionuclides may be calculated on the same basis.
2 This allows only for the radiological properties of uranium, not for its chemical toxicity.
Derived concentrations for radioactivity in water intended for human consumption1
Origin	Radionuclide	Derived concentration (Bq/1)
Natural	U-2382	3.0
	U-2342	2.8
	Ra-226	0.5
	Ra-228	0.2
	Pb-210	0.2
	Po-210	0.1
Artificial	C-14	240
	Sr-90	4.9
	Pu-239 / Pu-240	0.6
	Am-241	0.7
	Co-60	40
	Cs-134	7.2
	Cs-137	11
	I-131	6.2
Notes

Textual Amendments

F20 OJ L 159, 29.6.1996, p. 1, as amended by Corrigendum (OJ L 314, 4.12.1996, p. 20).

Screening for gross alpha activity and gross beta activity S

3.— (1) The monitoring local authority may use screening strategies for gross alpha activity and gross beta activity (or, where appropriate, residual beta activity after subtraction of the potassium-40 activity) to monitor a supply referred to in paragraph 1 for total indicative dose.

(2) Subject to sub-paragraph (3), screening levels must be set at—

(a) 0.1 Bq/l for gross alpha activity; and

(b) 1.0 Bq/l for gross beta activity.

(3) The monitoring local authority may set alternative levels to those specified in sub-paragraph (2) if it can demonstrate that these will ensure that a total indicative dose of 0.1 mSv is not exceeded.

(4) If the gross alpha activity is less than 0.1 Bq/l and the gross beta activity is less than 1.0 Bq/l, the monitoring local authority may assume that the total indicative dose is less than 0.1 mSv.

(5) Where sub-paragraph (4) applies, the monitoring local authority is not required to carry out a radiological investigation unless it is aware—

(a) that specific radionuclides are present in the water; and

(b) that these are liable to cause an indicative dose in excess of 0.1 mSv.

(6) If the gross alpha activity exceeds 0.1 Bq/l or the gross beta activity exceeds 1.0 Bq/l, the monitoring local authority must carry out an analysis for specific radionuclides.

(7) The monitoring local authority must, in deciding which radionuclides require to be measured for the purposes of sub-paragraph (6), take into account all relevant information about likely sources of radioactivity.

(8) If elevated levels of tritium are detected in a sample, the monitoring local authority must also measure the gross alpha activity and gross beta activity in that sample.

Calculation of the total indicative dose S

4.— (1) The total indicative dose must be calculated from—

(a) the measured radionuclide concentrations and the dose coefficients laid down in Table (A) of Annex III to Council Directive 96/29/Euratom F21 ; or

(b) more recent information recognised by the Scottish Ministers,

on the basis of an annual intake of water of 730 litres for adults.

(2) Where the following formula is satisfied, the monitoring local authority may assume that the total indicative dose is less than 0.1 mSv and that no further investigation is required—

where—

“C_i (obs)” refers to the observed concentration of radionuclide “i”;

“C_i (der)” refers to derived concentration of radionuclide “i”; and

“n” refers to the number of radionuclides detected.

Textual Amendments

F21 Table (A) lays down ingestion dose coefficients for members of the public.

Performance characteristics and methods of analysis S

5.   For each parameter or radionuclide listed in column 1 of the table below, the method of analysis used must be capable of measuring activity concentrations with at least the limit of detection specified for that parameter or radionuclide in column 2.

1 The limit of detection must be calculated according to the ISO standard 11929:2010 entitled “Determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measurements of ionising radiation - Fundamentals and application” (as it was first published), with probabilities of errors of 1st and 2nd kind of 0.05 each.
2 Measurement uncertainties must be calculated and reported as complete standard uncertainties, or as expanded standard uncertainties with an expansion factor of 1.96, according to the ISOIEC Guide 98-3:2008 entitled “Guide to the expression of uncertainty inmeasurement” (as it was first published).
3 The limit of detection for tritium and for radon is 10% of the corresponding prescribed concentration or value for the parameter.
4 The limit of detection for gross alpha activity and gross beta activities is 40% of the screening values of 0.1 Bq/l and 1.0 Bq/l respectively.
5 This limit of detection applies only to initial screening for total indicative dose for a new water source. If initial checking indicates that it is unlikely that Ra-228 exceeds 20% of the derived concentration, the limit of detection may be increased to 0.08 Bq/l for routine Ra-228 nuclide specific measurements, until a subsequent re-check is required.]
Parameter / radionuclide	Limit of detection (in Bq/l12
Tritium	103
Radon	103
gross alpha activity	0.044
gross beta activity	0.44
U-238	0.02
U-234	0.02
Ra-226	0.04
Ra-228	0.025
Pb-210	0.02
Po-210	0.01
C-14	20
Sr-90	0.4
Pu-239 / Pu-240	0.04
Am-241	0.06
Co-60	0.5
Cs-134	0.5
Cs-137	0.5
I-131	0.5
Notes—