The Water Supply (Water Quality) Regulations (Northern Ireland) 2007

Regulations 2 and 4

SCHEDULE 1 PRESCRIBED CONCENTRATIONS AND VALUES

TABLE A: MICROBIOLOGICAL PARAMETERS

Part I: Directive requirements

Item	Parameters	Concentration or Value (maximum)	Units of measurement	Point of Compliance(*)
(*) Where water is supplied from a tanker see regulation 4(3)(a)
1.	Enterococci	0	number/100ml	Consumers’ taps
2.	Escherichia coli (E. coli)	0	number/100ml	Consumers’ taps

Part II: National requirements

Item	Parameters	Concentration or Value (maximum)	Units of measurement	Point of Compliance
(**) Compliance required as to 95% of samples taken for coliform bacteria from each service reservoir (regulation 4(6)).
1.	Coliform bacteria	0	number/100ml	Service reservoirs(**) and water treatment works
2.	Escherichia coli (E. coli)	0	number/100ml	Service reservoirs and water treatment works

TABLE B: CHEMICAL PARAMETERS

Part I: Directive requirements

Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
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 also regulation 6(6). (iii) See also regulation 4(2)(d). (iv) See the definition of “pesticides and related products” in regulation 2. (v) The parametric value applies to each individual pesticide. (vi) “Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure. (vii) The specified compounds are: 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. (viii) The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process. (ix) The specified compounds are: 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.
1.	Acrylamide	0.10	µg/l	(i)
2.	Antimony	5.0	µgSb/l	Consumers’ taps
3.	Arsenic	10	µgAs/l	Consumers’ taps
4	Benzene	1.0	µg/l	Consumers’ taps
5	Benzo(a)pyrene	0.010	µg/l	Consumers’ taps
6	Boron	1.0	mgB/l	Consumers’ taps
7	Bromate	10	µgBrO3/l	Consumers’ taps
8	Cadmium	5.0	µgCd/l	Consumers’ taps
9	Chromium	50	µgCr/l	Consumers’ taps
10	Copper (ii)	2.0	mgCu/l	Consumers’ taps
11	Cyanide	50	µgCN/l	Consumers’ taps
12	1, 2 dichloroethane	3.0	µg/l	Consumers’ taps
13	Epichlorohydrin	0.10	µg/l	(i)
14	Fluoride	1.5	mgF/l	Consumers’ taps
15	Lead (ii)	(a) 25, from 25th December 2003 until immediately before 25th December 2013	µgPb/l	Consumers’ taps
		(b) 10, on and after 25th December 2013	µgPb/l	Consumers’ taps
16	Mercury	1.0	µgHg/l	Consumers’ taps
17	Nickel (ii)	20	µgNi/l	Consumers’ taps
18	Nitrate (iii)	50	mgNO3/l	Consumers’ taps
19	Nitrite (iii)	0.50	mgNO2/l	Consumers’ taps
		0.10		Treatment works
20	Pesticides (iv) (v) Aldrin Dieldrin Heptachlor Heptachlor epoxide	0.030	µg/l	Consumers’ taps
	other pesticides	0.10	µg/l	Consumers’ taps
21	Pesticides: Total (vi)	0.50	µg/l	Consumers’ taps
22	Polycyclic aromatic hydrocarbons (vii)	0.10	µg/l	Consumers’ taps
23	Selenium	10	µgSe/l	Consumers’ taps
24	Tetrachloroethene and Trichloroethene (viii)	10	µg/l	Consumers’ taps
25	Trihalomethanes: Total (ix)	100	µg/l	Consumers’ taps
26	Vinyl chloride	0.50	µg/l	(i)

Part II: National requirements

Item	Parameters	Concentration or Value (maximum unless otherwise stated)	Units of measurement	Point of compliance
1.	Aluminium	200	µgAl/l	Consumers’ taps
2.	Colour	20	mg/l Pt/Co	Consumers’ taps
3.	Hydrogen ion	10.0	pH value	Consumers’ taps
		6.5 (minimum)	pH value
4.	Iron	200	µgFe/l	Consumers’ taps
5.	Manganese	50	µgMn/l	Consumers’ taps
6.	Odour	3 at 25°C	Dilution number	Consumers’ taps
7.	Sodium	200	mgNa/l	Consumers’ taps
8.	Taste	3 at 25°C	Dilution number	Consumers’ taps
9.	Tetrachloromethane	3	µg/l	Consumers’ taps
10.	Turbidity	4	NTU	Consumers’ taps

Part II: National requirements

Item	Parameters	Concentration or Value (maximum unless otherwise stated)	Units of measurement	Point of compliance
1.	Aluminium	200	µgAl/l	Consumers’ taps
2.	Colour	20	mg/l Pt/Co	Consumers’ taps
3.	Hydrogen ion	10.0	pH value	Consumers’ taps
		6.5 (minimum)	pH value
4.	Iron	200	µgFe/l	Consumers’ taps
5.	Manganese	50	µgMn/l	Consumers’ taps
6.	Odour	3 at 25°C	Dilution number	Consumers’ taps
7.	Sodium	200	mgNa/l	Consumers’ taps
8.	Taste	3 at 25°C	Dilution number	Consumers’ taps
9.	Tetrachloromethane	3	µg/l	Consumers’ taps
10.	Turbidity	4	NTU	Consumers’ taps

Regulations 2 and 4

SCHEDULE 2 INDICATOR PARAMETERS

Item	Parameters	Specification Concentration or Value (maximum) or State	Units of Measurement	Point of monitoring
(*) May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution
Notes: (i) The water should not be aggressive. (ii) Excluding tritium, potassium-40, radon and radon decay products.
1	Ammonium	0.50	mgNH4/l	Consumers’ taps
2	Chloride (i)	250	mgCl/l	Supply point(*)
3	Clostridium perfringens (including spores)	0	Number/100ml	Supply point(*)
4	Coliform bacteria	0	Number/100ml	Consumers’ taps
5	Colony counts	No abnormal change	Number/1ml at 22°C Number/1ml at 37°C	Consumers’ taps, service reservoirs and treatment works
6	Conductivity (i)	2500	µS/cm at 20°C	Supply point(*)
7	Hydrogen ion	9.5	pH value	Consumers’ taps
8	Sulphate (i)	250	mgSO4/l	Supply point(*)
9	Total indicative dose (for radioactivity) (ii)	0.10	mSv/year	Supply point(*)
10	Total organic carbon (TOC)	No abnormal change	mgC/l	Supply point(*)
11	Tritium (for radioactivity)	100	Bq/l	Supply point(*)
12	Turbidity	1	NTU	Treatment works

SCHEDULE 3 MONITORING

TABLE 1: PARAMETERS AND CIRCUMSTANCES FOR CHECK MONITORING

(1)	(2)	(3)
Item	Parameter	Circumstances
1	Aluminium	When used as flocculant or where the water originates from, or is influenced by, surface waters
2	Ammonium
3	Clostridium perfringens (including spores)	Where the water originates from, or is influenced by, surface waters
4	Coliform bacteria
5	Colony Counts
6	Colour
7	Conductivity
8	Escherichia coli (E. coli)
9	Hydrogen ion
10	Iron	When used as flocculant or where the water originates from, or is influenced by, surface waters
11	Manganese	Where the water originates from, or is influenced by, surface waters
12	Nitrate	When chloramination is practised
13	Nitrite	When chloramination is practised
14	Odour
15	Taste
16	Turbidity

Table 2: ANNUAL SAMPLING FREQUENCIES: WATER SUPPLY ZONES

(1)	(2)	(3)	(4)
Substances and parameters subject to check monitoring	Estimated population of water supply zone	Reduced	Standard
(*) Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (ii) and (iii) below.
Notes: (i) Where the population is not an exact multiple of 5,000, the population figure should be rounded up to the nearest multiple of 5,000. (ii) Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required. (iii) Audit monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, audit monitoring is required at supply points. (iv) To monitor for total indicative dose (for radioactivity).
E. coli	<100		4
Coliform bacteria	≥100		12 per 5,000 population (i)
Residual disinfectant
Aluminium
Ammonium
Clostridium perfringens
(including spores)*
Colony counts
Colour	<100	1	2
Conductivity*	100-4,999	2	4
Hydrogen ion	5,000-9,999	6	12
Iron	10,000-29,999	12	24
Manganese	30,000-49,999	18	36
Nitrate (ii)	50,000-79,999	26	52
Nitrite (ii)	80,000-100,000	38	76
Odour
Taste
Turbidity
Aluminium
Antimony
Arsenic
Benzene(*)
Benzo(a)pyrene
Boron(*)
Bromate (iii)
Cadmium
Chromium
Copper
Cyanide(*)
1,2 dichloroethane(*)	<100		1
Enterococci	100-4,999		4
Fluoride(*)	5,000-100,000		8
Iron
Lead
Manganese
Mercury(*)
Nickel
Nitrate (ii)
Nitrite (ii)
Pesticides and related products(*)
Polycyclic aromatic hydrocarbons
Selenium
Sodium
Trichloroethene/Tetrachloroethene(*)
Tetrachloromethane(*)
Trihalomethanes	<100		1
Chloride(*)	100-4,999		4
Sulphate(*)	5,000-100,000		8
Total organic carbon(*)
Tritium(*)
Gross alpha(*) (iv)
Gross beta(*) (iv)

TABLE 3: ANNUAL SAMPLING FREQUENCIES: TREATMENT WORKS OR SUPPLY POINTS^(*)

(1)	(2)	(3)		(4)	(5)
Item	Substances and parameters	Volume of water supplied m3/d		Reduced	Standard
(*) Sampling is at treatment works for the substances and parameters shown in column (1) of the Table as items 1 to 6 and at supply points for the other substances and parameters, except nitrite, subject to notes (ii) and (iii); (i) Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3). (ii) Sampling at treatment works when chloramination is practised. (iii) Sampling at treatment works when chloromination is not practised. (iv) Audit monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, audit monitoring is required in water supply zones. (v) To monitor for total indicative dose (for radioactivity).
1	E. coli	<20			4
2	Coliform bacteria	20-1,999		12	52
3	Colony counts	2,000-5,999		52	104
4	Nitrite (ii)	6,000-11,999		104	208
5	Residual disinfectant	≥12,000		104	365
6	Turbidity
Subject to check monitoring
7	Clostridium perfringens (i)	<20			2
		20-999	2		4
8	Conductivity	1,000-1,999	6		12
		2,000-5,999	12		24
		6,000-9,999	18		36
		10,000-15,999	26		52
		16,000-32,999	52		104
		33,000-49,999	78		156
		50,000-67,999	104		208
		68,000-84,999	130		260
		85,000-101,999	156		312
		102,000-119,999	183		365
		120,000-241,999	365		730
		242,000-484,999	730		1,460
		485,000-728,999	1,095		2,190
Subject to audit monitoring
9	Benzene
10	Boron
11	Bromate (iv)
12	Cyanide
13	1,2 dichloroethane	<20			1
14	Fluoride	20-999			4
15	Mercury	1,000-49,999			8
16	Nitrite (iii)	50,000-89,999			12
17	Pesticides and	90,000-299,999			24
	related products	300,000-649,999			36
18	Trichloroethene	≥650,000			48
	Tetrachloroethene
19	Tetrachloromethane
20	Chloride
21	Sulphate
22	Total organic carbon
23	Tritium
24	Gross alpha (v)
25	Gross beta (v)

SCHEDULE 4 ANALYTICAL METHODOLOGY

TABLE A1: PARAMETERS FOR WHICH, SUBJECT TO REGULATION 16(7), METHODS OF ANALYSIS ARE PRESCRIBED

(1)	(2)
Parameter	Method
Clostridium perfringens (including spores)	Membrane filtration followed by anaerobic incubation of the membrane on m-CP agar* 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 microorganisms	PrEN ISO 6222
Colony count 37°C-enumeration of culturable microoganisms	prEN ISO 6222
Enterococci	ISO 7899-2
Escherichia coli (E. coli)	ISO 9308-1
*The composition of m-CP agar is:
Basal medium
Tryptose	30.0g
Yeast extract	20.0g
Sucrose	5.0g
L-cysteine hydrochloride	1.0g
MgSO4.7H2O	0.1g
Bromocresol purple	40.0mg
Agar	15.0g
Water	1,000.0ml
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	400.0mg
Polymyxine-B sulphate	25.0mg
Indoxyl-[beta]-D-glucoside	60.0mg
to be dissolved in 8ml sterile water before addition
Filter-sterilised 0.5% phenolphthalein diphosphate solution	20.0ml
Filter-sterilised 4.5% FeCl3.6H2O	2.0ml

TABLE A2: PARAMETERS IN RELATION TO WHICH METHODS OF ANALYSIS MUST SATISFY PRESCRIBED CHARACTERISTICS

(1)	(2)	(3)	(4)
Parameters	Trueness % of prescribed concentration or value or specification	Precision % of prescribed concentration or value or specification	Limit of detection % of prescribed concentration or value or specification
Notes: (i) The method of analysis should determine total cyanide in all forms. (ii) The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned. (iii) The performance characteristics apply to the individual substances specified at 25% of the parametric value in Part I of Table B in Schedule 1. (iv) The performance characteristics apply to the individual substances specified at 50% of the parametric value in Part I of Table B in Schedule 1. (v) The performance characteristics apply to the prescribed value of 4 NTU. (vi) The performance characteristics apply to the specification of 1 NTU for water leaving treatment works.
Aluminium	10	10	10
Ammonium	10	10	10
Antimony	25	25	25
Arsenic	10	10	10
Benzene	25	25	25
Benzo(a)pyrene	25	25	25
Boron	10	10	10
Bromate	25	25	25
Cadmium	10	10	10
Chloride	10	10	10
Chromium	10	10	10
Colour	10	10	10
Conductivity	10	10	10
Copper	10	10	10
Cyanide (i)	10	10	10
1,2-dichloroethane	25	25	10
Fluoride	10	10	10
Iron	10	10	10
Lead	10	10	10
Manganese	10	10	10
Mercury	20	10	20
Nickel	10	10	10
Nitrate	10	10	10
Nitrite	10	10	10
Pesticides and related products (ii)	25	25	25
Polycyclic aromatic hydrocarbons (iii)	25	25	25
Selenium	10	10	10
Sodium	10	10	10
Sulphate	10	10	10
Tetrachloroethene (iv)	25	25	10
Tetrachloromethane	20	20	20
Trichloroethene (iv)	25	25	10
Trihalomethanes:	25	25	10
Total (iii)
Turbidity (v)	10	10	10
Turbidity (vi)	25	25	25