Water quality
Water quality is checked at every stage on its journey to your taps. At the treatment works it is monitored 24 hours a day, 365 days a year, to ensure that the water is always safe to drink.
At other places in the water network samples are taken throughout the year for analysis at our laboratory.
Every year our results are checked by the Government's Drinking Water Inspectorate (DWI). They do this to make sure we are operating our water treatment works and distribution system in a way that doesn't put your water supply at risk.
During each year over 200,000 tests are carried out and our pass rate currently stands at 99.9%. This is higher than the national average.
Some of the things we check for
Naturally occurring substances that we have to check for include calcium, especially where it flows through limestone or chalk. Sulphate, magnesium, sodium and potassium as a result of its passage through minerals as well as manganese, iron, aluminium, nitrates and phosphorus.
Other substances that we have to check for include copper and zinc, lead, pesticides (which are removed through the treatment process), PAH (polynuclear aromatic hydrocarbons) and bacteria.
Small amounts of chlorine are added to water as it leaves the treatment works to kill any bacteria present and to keep the water safe on its way to your tap. Fluoride is also added to around 40% of the water supply in the north east of England, at the request of the local authorities. The areas affected include much of Northumberland, Tyne and Wear and north west Durham.
Sample sheet showing the official standards of the elements tested in a water sample.