Our chalk stream commitment

In the last decade, we have invested more than £230m to reduce the amount of water we take by 25Ml/d to preserve the unique ecology of our rivers.

Why is chalk stream health important?

Chalk stream health is affected by flow (comprising groundwater baseflow and surface runoff), water quality, morphology and management. When all these elements are optimised, the unique ecology will flourish.

All chalk rivers are fed from natural underground aquifers and as a result they have clean and clear water. These conditions, along with their alkaline chalk geology, support a rich diversity of wildlife, including important fish populations such as brown trout, native crayfish and many other specialist species.

How do we protect chalk streams?

The water we supply to our customers comes from the local environment and approximately 75% from boreholes and springs that tap into the chalk and Upper Greensand aquifers of Wiltshire and Dorset.

For decades we have sought to balance the need to supply water to our customers without compromising healthy flows in our chalk streams, and we have taken steps to minimise the impact of our abstractions. In the last decade alone, we have invested more than £230 million to reduce the amount of water we take by 25 million litres per day to preserve the unique ecology of these rivers.

We also ensure that customers’ sewage is conveyed and treated at our water recycling centres before being safely returned to the rivers. We have invested £50 million to improve our water recycling centres (WRCs) to remove increasing levels of nutrients from the sewage and reduce our impacts.

We are also investing £150 million between 2020 and 2025 to reduce the impact storm overflows have on the environment, which will benefit chalk streams across the region.


What are the challenges?

There are numerous challenges to ensure improvements are made to chalk streams. The key challenges include:

  • balancing water abstractions with demand for water while maintaining chalk stream habitats and complying with all relevant legislation
  • improving sewage treatment to cater for increased waste from developments and providing a greater level of phosphorus removal
  • reducing the operation of storm overflow.

There are no simple fixes to these challenges, and we are keen to deliver the most sustainable solutions possible, including nature-based solutions.

There is also a need for legislative changes, partnership working and increased education and awareness solutions, not all of which rest with Wessex Water.

How have we performed so far


chalk stream projects delivered in the last 20 years


reduction in leakage since 1995


abstraction reduction due to water supply grid

New mission to help Dorset chalk stream thrive

Flagship Chalk Stream announcement

We have chosen the River Frome, Hooke and Wraxall Brook in Dorset to be our Flagship Chalk Stream for restoration by 2035, reporting to the national Catchment Based Approach (CaBA) Chalk Streams Group.