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3. Introduction
3.1 Role of the Regulator
The quality of drinking water in Scotland is regulated by the Drinking Water Quality Regulator for Scotland ( DWQR). The DWQR is responsible for monitoring and confirming that drinking water supplied by Scottish Water meets the requirements of the Water Supply (Water Quality)(Scotland) Regulations 2001 and is safe to drink. Scottish Water is a publicly owned company and is the sole supplier of public drinking water in Scotland. The DWQR does not collect and analyse water samples; it closely monitors the quality of samples collected by Scottish Water to ensure they meet the required standard and have been taken at the prescribed frequencies. The DWQR also inspects and audits the facilities used by Scottish Water to analyse samples to ensure that the analysis and reporting of results is accurate.
Local authorities are responsible for monitoring the quality of the many small private water supplies in Scotland, but the DWQR has a role in ensuring that these responsibilities are undertaken satisfactorily. In 2005 these responsibilities were defined by the Private Water Supplies (Scotland) Regulations 1992, however, these have now been superseded by the Private Water Supplies (Scotland) Regulations 2006.
The post of Drinking Water Quality Regulator for Scotland was created in the Water Industry (Scotland) Act 2002. This placed the functions of the Regulator on a statutory footing. Although the DWQR has similar functions to those of the Drinking Water Inspectorate ( DWI) in England and Wales, the separation between Ministers and the Regulator is greater in Scotland than in England and Wales because Scottish Water is a publicly-owned body as opposed to the privately-owned companies in England and Wales. In Scotland the DWQR is responsible for enforcing The Water Supply (Water Quality) (Scotland) Regulations independently of Ministers, whereas the DWI carries out this role on behalf of Ministers.
3.2 Powers of the Regulator
The DWQR has three main powers. These are in respect of the power to obtain information, the power of entry or inspection and the power of enforcement. The DWQR can vary and/or withdraw enforcement notices but he must keep a register of any notices issued. In addition, the DWQR has emergency powers to require a water supplier to carry out works to ensure that the quality of water supplied is safe for public consumption. DWQR can also instruct a local authority to provide information held by it with regard to enforcement undertaken by the local authority.
3.3 About this Report
Each year the Regulator must submit an annual report to Scottish Ministers. The annual report summarises and comments on the drinking water quality results for the preceding year. It also includes an account of any investigations or enforcement actions carried out by the Regulator during the period covered by the report.
This is the fourth such annual report that has been prepared by the Drinking Water Quality Regulator for Scotland and submitted to Scottish Ministers. It presents and reviews the information provided by Scottish Water under the Water Supply (Water Quality) (Scotland) Regulations 2001 and reflects the dealings that the DWQR had with Scottish Water between 1 January and 31 December 2005. The report also presents and reviews information on private supplies provided by the local authorities.
This report is structured slightly differently to previous years in order to present more information about water quality at a local level and to include more information on private supplies, Cryptosporidium and consumer complaints. Section 4 of the report covers the subject at a national level, examining the water quality in sources, at water treatment works, and through the distribution system to consumers' taps. Section 5 breaks the national results down into the five regions of Scotland representing WaterWatch Scotland panel areas, which allows comparisons to be made between regions. Section 6 retains the local authority pages used in previous reports, providing greater detail on drinking water quality at consumers' taps and of water quality incidents.
Throughout the report reference is made to the need for action where non-trivial breaches of the standards set in the 2001 Regulations have been identified. If Scottish Water is not able to take action quickly to remedy such a breach then Scottish Water will normally apply to Scottish Ministers for an Authorised Departure which will apply while steps are taken to secure compliance. If Scottish Ministers do not receive an appropriate application for an Authorised Departure, enforcement action can be taken. Details of Authorised Departures granted by Scottish Ministers in 2004 are listed in Annex F. No enforcement action was taken against Scottish Water in 2005.
3.4 The 10 Key Drinking Water Quality Standards in Scotland
The Water Supply (Water Quality) (Scotland) Regulations 2001 set out the quality standards that drinking water must meet and define the frequency at which Scottish Water is required to test for each parameter. Ten key drinking water quality standards have been identified which are of particular significance when considering the quality of drinking water in Scotland. They have been selected because they are of particular relevance to Scotland and provide a useful indication of water quality or because they are parameters which have a higher regulatory frequency of sampling. The 10 Key Drinking Water Quality Standards in Scotland are shown below, together with the Prescribed Concentration or Value ( PCV) set out in the regulations:
Parameter | Significance |
|---|
Total Coliforms PCV 0 per 100ml Sampled at treatment works, service reservoirs in the distribution system and at consumers' taps. | The coliform group of bacteria is present in large numbers in the gut of all warm-blooded animals but is also widely distributed in the environment. While their presence in water supplies may indicate a breach in the integrity of the water supply system or a failure of the treatment process, it may not be presumed that faecal pollution has occurred. It is generally considered that coliforms themselves do not present a risk to health, however they are a useful indicator in monitoring the quality of water supplies. |
Faecal Coliforms PCV 0 per 100ml Sampled at treatment works, service reservoirs in the distribution system and at consumers' taps. | Faecal coliforms are present in large numbers in the gut of all warm-blooded animals. Their presence in water supplies indicates a breach in the integrity of the water supply system and that faecal pollution may have occurred. The detection of faecal coliforms in a water supply is taken very seriously. |
Colour PCV 20 mg/l Pt/Co Sampled at consumers' taps. | Colour in water comes from naturally occurring humic substances, particularly in acidic water sources derived from peaty moorland catchment areas. High colour may be unacceptable to consumers on aesthetic grounds and the humic substances responsible for colour may form other compounds when the water is disinfected. Colour may be removed by appropriate treatment. |
Turbidity PCV 4 NTU Sampled at consumers' taps (1 NTU standard applies at treatment works). | Turbidity is a measure of the "cloudiness" of the water. Naturally occurring turbidity is usually caused by the suspension of tiny particles of predominantly inorganic origin. High turbidity may be a result of poor control of the treatment process, particularly the coagulation and filtration stage, and could indicate that the treatment process has not provided an effective barrier against organisms such as Cryptosporidium. Turbidity is unacceptable to consumers on aesthetic grounds and may also compromise disinfection. |
Hydrogen Ion (pH) PCV 6.5 - 9.5 Sampled at consumers' taps. | Most surface waters and many groundwaters in Scotland are slightly corrosive towards the materials used in water treatment systems and consumers' installations. This effect persists even when the pH is above neutral (pH7) and is countered by adding an alkali during treatment to raise the pH. As chlorine disinfection is more effective at low pH addition of alkali is normally made after the disinfection stage. Extreme pH values may present a risk to the health of consumers. |
Aluminium PCV 200 µg/l Sampled at consumers' taps. | Aluminium occurs in acidic waters derived from moorland catchments and is removed in water treatment by coagulation and filtration. Aluminium sulphate is used as a coagulant in water treatment. High concentrations are unacceptable to consumers on aesthetic grounds. |
Iron PCV 200 µg/l Sampled at consumers' taps. | Iron is present naturally in many water sources and is removed by conventional water treatment processes. Iron in water supplies may also be derived from corrosion of iron water mains and poor control of water treatment processes. High iron concentrations are unacceptable to consumers on aesthetic grounds as they may cause discoloured supplies. |
Manganese PCV 50 µg/l Sampled at consumers' taps. | Manganese occurs naturally in many water sources. It may be removed from water by using an appropriate treatment process. Where treatment processes do not remove manganese, it may accumulate in water mains as a sediment or coating. Elevated manganese concentrations are unacceptable to consumers on aesthetic grounds as they may cause discoloured supplies. |
Lead PCV 25 µg/l Sampled at consumers' taps (reduces to 10µg/l in 2013). | Lead is not normally naturally present in water sources but significant concentrations may be present at consumers' taps if lead pipes have been used in the internal household plumbing or service pipe that connects the property to the main in the street. Many waters in Scotland have a tendency to dissolve lead from lead pipework, but phosphate compounds can often be dosed at the treatment works to reduce this tendency. |
Trihalomethanes PCV 100 µg/l for total of four of the compounds. Sampled at consumers' taps. | Trihalomethanes ( THMs) are a range of compounds which occur in drinking water principally as products of the reaction of chlorine with naturally occurring organic materials present in the water. Treatment processes can be adapted to minimise their formation or to remove the precursor compounds. Many water supplies in Scotland contain significant quantities of the precursor compounds which can form THMs, which makes control of the treatment process particularly important. A number of Authorised Departures have been granted in Scotland to enable Scottish Water to improve supplies which do not currently meet the standard for THMs. |
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Cryptosporidium
Although not one of the 10 key parameters, Cryptosporidium is closely monitored in drinking water supplies in Scotland. Cryptosporidium is a microscopic protozoan parasite which can live in the gut of humans and warm blooded animals. There are a number of species of Cryptosporidium, not all of which are thought to be infectious to humans. All species form oocysts which can survive in the environment for long periods. Once ingested, Cryptosporidium multiplies rapidly in the gut and oocysts are excreted in very large numbers, completing the life cycle of the organism. In humans, infection can cause stomach cramps and diarrhoea and, in extreme cases, can be fatal to the immuno-compromised or to the very young or old.
Cryptosporidium can enter a water supply if faecal material is washed into the source (raw) water and any oocysts are not removed by the treatment process. Standard chlorine disinfection is not generally effective against oocysts, so removal using a filter barrier is the accepted process. The Cryptosporidium (Scottish Water) Directions 2003 set out the measures Scottish Water is expected to take in monitoring and operating assets to prevent oocysts from contaminating drinking water supplies.
3.5 Contacting the Regulator
If you are concerned about the quality of the drinking water in your home or place of work, in the first instance you should contact Scottish Water and ask them to investigate.
Scottish Water
PO Box 8855
Edinburgh
EH10 6YQ
Tel 0845 601 8855
If, having discussed the matter with Scottish Water, you do not feel that the issue has been satisfactorily resolved, you should contact the Drinking Water Quality Regulator for Scotland. The DWQR can investigate on your behalf and take action if necessary. DWQR will inform you of the outcome of any investigation.
The DWQR may be contacted either by writing to:
Drinking Water Quality
Regulator for Scotland
PO Box 23598
EDINBURGH
EH6 6WW
or emailing regulator@dwqr.org.uk.
When contacting DWQR, please provide as much information as possible, including the address of the property where the problem has occurred, the nature and duration of your concerns and details of any contact you have had with Scottish Water regarding the problem.
Please note that the DWQR can only investigate concerns relating to the quality of public drinking water supplies in Scotland.
For matters concerning private supplies in Scotland you should contact the Environmental Health Department of your local council. The website www.privatewatersupplies.gov.uk contains further information on private water supplies.
For matters concerning services provided by Scottish Water other than the quality of the water supplied you should contact WaterWatch Scotland: info@waterwatchscotland.org
For information on the quality of public supplies elsewhere in the UK you should contact the Drinking Water Inspectorate ( DWI) for England or Wales or the Northern Ireland Drinking Water Inspectorate. The DWQR works closely with both of these organisations to ensure a consistent approach is taken towards ensuring the quality of drinking water across the UK. A Memorandum of Understanding between the three bodies can be found on the DWQR website: www.dwqr.org.uk
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