DRINKING water in Scotland is below the standard of that in England and Wales, a study has found.
In its annual report, the Drinking Water Quality Regulator (DWQR) said 99.86 per cent of samples taken from consumers’ taps in 2012 complied with standards – Scottish Water’s best performance – but the proportion of contaminants did not consistently achieve the same level as south of the Border.
It also expressed concern that many private water supplies posed a risk to the public.
Almost 3 per cent of more than 1,554 samples taken from customers’ taps did not comply with standards for trihalomethanes, chemical compounds that have been linked to long-term health problems, including cancer. Those accounted for 19 per cent of the total failed samples.
Almost one in three of the samples that did not meet standards contained a bacteria called coliform. Only two samples were contaminated with E coli.
The report raised concerns about private water supplies such as wells, which are more common in rural Scotland than elsewhere in the UK. Some 15 per cent of private water supply tests found contamination with E coli and a third revealed the presence of coliform bacteria.
The report pointed to data tracking Scotland’s water quality standards against those in England and Wales.
“[It] shows that compliance in Scotland has improved considerably in the ten years since Scottish Water was formed,” it said. “It also shows that there is more to do before water quality in Scotland consistently achieves the same standard as that in England and Wales.”
Trihalomethanes are formed as a by-product when chlorine is used to disinfect water for drinking. The report said: “Trihalomethane compliance was similar to 2011, despite ongoing work by Scottish Water to reduce the number of failures due to this by-product of the disinfection process.
“DWQR takes the view that Scotland can and must achieve the same high level of compliance for this parameter that is seen elsewhere in the UK.”
Trisha McAuley, Scottish director of the Consumer Futures watchdog, said: “Scottish consumers can be confident that the quality of our public water supply is at an all-time high and that Scottish Water continues to improve on both quality standards and customer responsiveness.”
Private water supplies are not the responsibility of Scottish Water but of their owners and users. However, they must comply with regulations. Grants of £800 are available on a non-means-tested basis to anyone wanting to upgrade their private water supply.
“For too many consumers who have to depend on a private water supply, the standard of water remains completely unacceptable and a risk to health,” Ms McAuley said.
A Scottish Water spokesman said it was working to “optimise” its treatment processes to cut the levels of trihalomethane and added that it had replaced or improved 25 water treatment works and more than 635 miles of pipes over the past year.
“We welcome the DWQR’s report and confirmation that the quality of Scotland’s public drinking water is at an all-time high,” he said.
Scottish Water received 17,776 consumer “contacts” over water quality last year – the majority about discoloured supplies – a 31 per cent fall on the 2011 figure.
Quality on tap?
Coliform bacteria: Although not harmful in themselves, the presence of the bacteria, which comes from faeces, indicates other waterborne pathogens could be present.
Trihalomethanes: Formed as a by-product when chlorine is used to disinfect water
for drinking. Have been linked to a range of long-term health issues, including cancer.
Iron and Manganese: High levels of iron and manganese in water can cause sediment, which occasionally can contain trace impurities or harbour bacteria that can be harmful.
Lead: Very high levels of lead can result in delays in physical and mental development in children and high blood pressure in adults.
Hydrogen Ion: This indicates whether the water is acid or alkaline.
Pesticides: These could have long-term health effects if found at high levels.
Nitrite: High levels may cause methemoglobinemia in infants who drink water or formula made from water containing nitrate levels higher than recommended.
Taste: Taste, odour or discolouration problems can occasionally be found.
Ammonium: Can interfere in disinfection of water.
Benzi 3,4 Pyrene: Long-term exposure at high levels could cause reproductive difficulties or be linked to a higher risk of cancer.