Community action needed to protect Henllan Brook from pollution
Natural Resources Wales (NRW) is calling on the Denbigh community to help tackle pollution affecting Henllan Brook.
NRW officers have been working closely with partners at Dŵr Cymru Welsh Water and Denbighshire County Council to trace sources of pollution in the area. This includes sampling sections of the watercourse, conducting river walks, and investigating drainage systems.
Recent investigations have revealed that misconnections from properties in the area are contributing to pollution in the brook. These issues, combined with both urban and rural pollution, have led to poor water quality by introducing nutrients, sediment and animal waste into the stream.
The help of residents is now required to prevent further harm to the local environment and wildlife. Misconnections often occur when wastewater pipes are wrongly connected to surface water drains, allowing pollutants to enter streams and rivers. These can come from bathrooms, kitchens, or household appliances.
Henllan Brook has suffered several incidents during 2025, including visible discolouration and cloudy looking water. While some previous issues, such as foam linked to local construction works, have now ceased, the brook continues to fail water quality standards.
Further sampling will take place soon to monitor changes under different weather conditions. Surveys by Dŵr Cymru have already identified issues, including a foul line leaking into a surface water drain from a local community centre, and a toilet from a domestic property incorrectly connected to the surface water line.
Rhys Ellis, NRW Environment Team Leader for Denbighshire, said:
“Henllan Brook is an important part of the local environment, and we need everyone’s help to protect it. Misconnections can have a serious impact on water quality and wildlife.
“Please check your property’s connection and if you notice pollution in the brook, please report it to NRW immediately before posting it on social media. Timely reports help us respond quickly and trace sources before evidence disappears.
“If you need to report an environmental or pollution incident, please contact our 24/7 incident communications centre via our online report it form. You can also contact us 24/7 on 0300 065 3000.”
Martin Williams, Sewerage Manager at Dŵr Cymru Welsh Water:
“Collaborative investigations like this are essential for protecting and improving our local environment. We’re proud to have contributed to the progress made on this river so far. There’s still work to be done, and it’s crucial that waste water is correctly connected to the sewer system—not into surface water drains. You can find guidance on how to check your property for misconnections here, and learn more by searching ‘ConnectRight’.”
A Denbighshire County Council spokesperson said:
“Denbighshire County Council supports NRW and Dwr Cymru in this investigation and we also encourage residents to check their drainage connections and when a misconnection is identified to take remedial action to prevent further harm to the local environment and wildlife.”