The Private Water Supplies (Scotland) Regulations 2006

Regulation 26

SCHEDULE 3 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.
(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 for Total indicative dose is achieved through screening for gross alpha and gross beta.	If a monitoring local authority is satisfied that on the basis of other monitoring carried out, the Total indicative dose in a supply is well below the prescribed value, the authority may seek a regulation 24 notice from the Scottish Ministers confirming that the supply need not be monitored in respect of Total indicative dose.
(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	Tritium is produced naturally in the upper atmosphere when cosmic rays strike air molecules. Tritium is also produced during nuclear weapons explosions, as a by-product in reactors producing electricity, and in special production reactors, where the isotope Lithium-6 is bombarded to produce Tritium.	If a monitoring local authority is satisfied that on the basis of other monitoring carried out, the level of Tritium in a supply is well below the prescribed value, the authority may seek a regulation 24 notice from the Scottish Ministers confirming that the supply need not be monitored for Tritium.
(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.