How your water is treated
- Where does the water in my taps come from?
All the water you get from your taps starts off by falling from the sky as rain, hail or snow. It is then collected, stored, cleaned and made safe to drink before being pumped to your house, ready for you to use.
On average, 60% of water in our area of supply comes from reservoirs and rivers and 40% comes from boreholes. Boreholes are deep wells that collect water that has soaked down through the ground to form underground water stores called aquifers. Groundwater is water that is collected and stored in reservoirs from rivers and streams.
We have three main sources of supply:
- A reservoir at Blithfield. This collects water falling as rain, hail and snow.
- Water is taken from the River Severn and stored in Chelmarsh reservoir.
- Approximately 62 boreholes across the area.
The amount of water that is taken from each of these sources is carefully managed to ensure that you do not go short of water, and the environment is not adversely affected.
- How is the water cleaned?
- Water needs to be treated to meet stringent drinking water standards before it can be used in your house. Water from rivers generally contains the most impurities and therefore needs the most treatment. Reservoir water is cleaner, but it still requires treatment.
In general water from rivers and reservoirs is treated in the following way:
- First the water is passed through huge sieves that catch and remove large bits of debris such as leaves, twigs and other floating rubbish.
- Then the smaller particles such as dirt, bacteria and metals are removed by adding carefully controlled amounts of chemicals to the water. This causes the small particles in the water to stick together, forming a dense layer (called floc) that sinks to the bottom, carrying with it the unwanted particles.
- The floc is now separated from the cleaned water by either: allowing it to settle as sludge in the bottom of a tank, where it is removed, or by injecting air into the bottom of the tank. Millions of minute bubbles then carry the floc to the top of the tank, where it is scraped off by brushes.
- The clear water then flows down through layers of gravel and carbon, which filters the water still further, removing any remaining traces of floc or other fine particles. In addition, the carbon removes traces of organic materials such as pesticides.
Water from boreholes will have already been naturally filtered during its passage down through the rocks and can often require only minimal treatment.
We supply over 330 million litres of clean drinking water to our customers every day—that's enough to fill 132 Olympic swimming pools.
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- How is water made safe to drink?
- Finally, to make this water safe to drink it must be freed of any remaining harmful germs or bacteria. This is done by disinfecting the water with chlorine. Disinfection with chlorine also ensures that the water remains safe to drink in our network of water pipes, right up to your tap.
There are over 5,600km of drinking water supply pipes buried underground in our area of supply—enough to stretch from Birmingham to Lisbon and back again!
- How is the water stored and then delivered to my taps?
This clean drinking water is now pumped from the water treatment works and put in huge covered storage tanks, called service reservoirs. These service reservoirs are generally on ground higher up than the area they serve, so that the water will flow with enough pressure through the pipes to your taps when you want it. Sometimes water must be pumped to where it is needed because of the nature and features of the surrounding land. This uses electricity, in fact pumping water accounts for 92% of the total costs whilst 6% is for treatment and 2% is for administration.
The clean water leaves the service reservoir through a network of underground pipes, called the water distribution mains.
The water mains carry the water to just outside your house. From here a service pipe connects the water mains to your house, usually with a valve called a stop tap. This stop tap is generally found underneath a cover in the pavement and allows you, or us, to turn off the water for repairs or maintenance. More information on stop taps.
You may also have another stop tap inside your house, probably underneath the kitchen sink, which you can use if you need to repair your household plumbing.
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