Where your water comes from

50% from rivers and reservoirs

Half the drinking water we supply comes from rivers and reservoirs in our region. It passes through complex treatment processes to make it safe to drink.


50% from underground sources

The rest of our water comes from underground water sources. These generally need less treatment than water from rivers or reservoirs.

Protecting water sources

We take water from hundreds of boreholes and more than a dozen rivers and are committed to working with other organisations to carefully manage these river and groundwater catchment areas. This is particularly important in the Anglian Water region, where agriculture, food and drink production has such a vital role in our regional economy.


We encourage farmers - who use fertilisers and pesticides to improve yields and protect crops against pest damage - to use their chemicals responsibly and keep them out of groundwater and river water sources.


Rising nitrate levels in surface water run-off and small amounts of pesticide compounds in water sourced from boreholes and rivers however, present us with a number of challenges.


We address these challenges by protecting and improving the quality of water in rivers and groundwater at source, reducing the need for expensive, energy intensive treatment processes.


How we treat the water

We supply over a billion litres of safe drinking water every day. How we treat raw water entering our water treatment works depends on the quality of the water source. Many underground supplies from boreholes are so clean we only need to add a small amount of chlorine to make them safe. Other underground water sources, and all river and reservoir water, need more complex treatment.

Ground Water


  1. We remove naturally occurring metals, such as iron and manganese, by oxidising and then filtering the water through sand and other filter materials
  2. Ion exchange treatment removes nitrates; we reduce concentrations by blending with water containing lower nitrate levels
  3. Granular activated carbon absorb pesticide residues and any compounds that make the water taste or smell
  4. We disinfect treated water with chlorine to ensure there are no harmful micro-organisms.


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Surface water

  1. Ozone oxidises pesticides and prepares the water for the next treatment stage
  2. Iron salts coagulate tiny particles in the water, increasing their size
  3. We filter these larger particles through anthracite and sand
  4. More ozone breaks down any remaining pesticides
  5. Granular activated carbon removes pesticide residues and any compounds that make the water taste or smell
  6. We disinfect treated water with chlorine.

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Your drinking water 


We store the water we supply to our millions of our customers in water towers and service reservoirs across our region. This means we always have supplies of water on standby, ready for times when demand is particularly high.


To move water around, we make use of gravity where we can. Our water towers help, but to keep water pressure constant in this mainly flat region, we pump water through thousands of kilometres of water mains.


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Keep water healthy

Before it gets to your tap, your drinking water is cleaned, disinfected and tested. However, sometimes it can get contaminated within your home.


Find out how to keep your water healthy and your supply at its very best – sparkling clean and healthy!