Warleigh Weir

Warleigh Weir

Warleigh Weir, a location along the River Avon near Bath, is visited by people who use the stretch of river for recreation, including swimming. 

We have been working with the landowner, the Rivers Trust, Bristol Avon Rivers Trust and the Environment Agency to discuss river water quality at the location, which can be affected by a number of factors – from our storm overflows and treated wastewater from our water recycling centres being returned to the river upstream to agricultural run-off, septic tanks, road drains and wild animals. 

In September 2020 intensive water quality monitoring took place, involving a partnership with The Rivers Trust with Bristol Avon Rivers Trust, Wessex Water, Sewage Free Swimmers and the Environment Agency, and a team of volunteers.  

To understand more about water quality at this location, investigative work is underway to find out more about the factors in the large river catchment upstream of the site which influence the condition of the river water and the role our assets have.

Warleigh Weir from the riverbank

Monitoring storm overflows 

Storm overflows act as relief valves, allowing excess stormwater to be released to rivers or the sea. This protects properties from flooding and prevents sewage backing up into streets and homes during heavy storm events.

We monitor when storm overflows are in use that affect bathing waters and information is provided on Coastwatch. This now includes information on when our storm overflows operate which affect some inland waters, including Warleigh Weir. You can find out the location of storm overflows and how often they are in use on our online mapping system.  

We have extended our notification system which now includes when the following sites are in use, which are upstream from Warleigh Weir: 

  • Culver Street, Bradford on Avon
  • Monkton Combe, Mill Lane
  • Freshford Water Recycling Centre (formerly known as sewage treatment works)

This information is sent to the landowner and anyone can use either our Coastwatch system or the Surfers Against Sewage SaferSeas (and Rivers) app to find out when they have operated. The SaferSeas app also allows you to register for live information on these overflows.   

What more can be done about overflows? 

All overflows are designed so the discharge does not impact on the environmental health of rivers. Current water quality data indicates that 13 waterbodies in the Wessex Water area are confirmed or are possibly affected by storm overflows. Whilst this is probably an incomplete picture, it provides a starting point for targeting overflows that cause harm. 

There is even less water quality information indicating how storm overflows affect public health risks for river users.  

So, we should aim to address overflows starting with the ones that have most impact.  This is not a simple matter and will require many decades of sustained and increased investment.  It is estimated that to eliminate all overflows in England and Wales, will cost in excess of £100 billion.   

Our programme starts with monitoring and reporting all overflow operations; identifying the ones that potentially cause environmental or public health harm, addressing those and then progressively working through the others.  Over our current five-year regulatory programme, we are committing a huge amount of effort into investigating the impacts of overflow operation and will be investing approximately £150million to begin to address the highest priority ones. 

To enable the principle of keeping surface water out of foul sewers and keep sewers flowing freely without blockages we are calling on Government to update legislation that would support this aim in the following areas: 

  • Stopping developers connecting surface water to combined sewers so making the current problems worse. 
  • Giving water companies the right to discharge surface water directly to watercourses. 
  • Banning the use of non-degradable wet wipes which are the major cause of blockages in the sewer network. 

You can find out more on our storm overflows page. 

Wild swimming

Wild swimming is an activity that takes place in some natural waters, such as rivers and lakes.


Coastwatch is our online overflow notification system which provides near real-time information of when storm overflows have operated at designated bathing waters and at other water bodies used regularly for recreation.