Area of Outstanding Natural Beauty

Mendip Hills

Polluted by sewage 452 times in 2025 - lasting 4,586 hours

Marker shade

Totals for Mendip Hills in 2025

12 Sites polluted by Wessex Water

452 sewage dumps

4,586 hours duration

Sewage pollution map of Mendip Hills, showing 452 overflows in 2025

That's 6.37 months. On average 1.2 times a day

How does Mendip Hills compare?

Mendip Hills was the #17 most polluted Area of Outstanding Natural Beauty in England & Wales, by duration of sewage overflows, as reported by the water companies

Why the change?

Storm overflows spill when it rains, and 2025 was drier than 2024 - 90% of average annual rainfall against 105%.

So much of any drop is weather, not fixed pipes. The live page shows rainfall and sewage side by side, day by day.

Live Data

Take Action

We need your support!

Please consider a one-off or small recurring donation. We need your help to keep this site going.

Donate Now

Constituencies

Pollution Summary 2025

Here are all the reported sewage overflow totals for Mendip Hills in 2025.

How we count, and how accurate it is

A CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway counts towards Mendip Hills when it sits inside the designated area, or within 200 metres of its boundary. An overflow close to two AONBs is counted in both.

We use data from the water companies, but we are seeing many anomalies that make us believe that location information is quite poor. The situation is likely far worse than reported here.

Other CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway s just outside the 200 metre boundary are not counted, though they may still affect water quality inside the area.

Company	Waterway	Site	Sewage Dumps	Duration (Hours)	Reporting %
Wessex Water	River Chew	EAST HARPTREE WRC	99	1,283	100
Wessex Water	Congresbury Yeo, Lake	UBLEY WATER RECYCLING CENTRE	50	945	99.8
Wessex Water	Lox Yeo	WINSCOMBE WWTW	57	864	100
Wessex Water	Congresbury Yeo And Butcombe	BUTCOMBE WATER RECYCLING CENTRE	44	817	99.3
Wessex Water	Congresbury Yeo	BLAGDON WASTEWATER TREATMENT WORKS	34	354	100
Wessex Water	River Chew	BISHOP SUTTON PUMPING STATION	62	117	100
Wessex Water	River Yeo	FROGLANDS PUMPING STATION	38	82	100
Wessex Water	River Chew	CHEW STOKE PUMPING STATION	50	74	100
Wessex Water	Cross Rhyne	CROSS EAST PUMPING STATION	6	19	100
Wessex Water	Lox Yeo	WINSCOMBE WWTW	3	17	100
Wessex Water	Towerhead Brook	SANDFORD BATCH PS	5	8	100
Wessex Water	River Axe Via Sws	KENNEL BATCH CSO	4	0	100

Data Sources & Accuracy

EDM (Event Duration Monitoring) data and Consented Discharges to Controlled Waters with Conditions from Environment Agency & Data Map Wales, and Scottish Water

Experimental derived data from Thames Water API, Some data may be missing or inaccurate. Live sewage data from Stream Water API

Annual figures up to and including 2025 come from official water company returns. The 2026 figure is our own estimate, derived continuously from the companies' live data feeds.

Uses Environment Agency rainfall data from the real-time data API (Beta) - Rainfall data is delayed by up to two days.

This website is intended to provide an accurate representation of the Environment Agency data. The data is hard to use, and thus some errors may have been made. If you find something that is incorrect, please raise an issue at the GitHub issues page and we'll endeavour to fix it quickly.

This project is not associated, approved or endorsed by any of the companies whose logos you see here.

Analysing sewage pollution by the Water Industry

Media Queries

Get in touch if you have queries or want to discuss our data.

press [at] top-of-the-poops.org

Please Support Us

We rely on donations to fund our work. Please support us if you can

Yes! Support TOTP!

© 2020-2025 Top-Of-The-Poops CC-BY-SA 4.0,
© Openstreetmap contributors, Contains OS data © Crown copyright and database right 2021-2025,
Contains Water UK National Storm Overflow Hub Data CC-BY-SA 4.0 and analysis © 2025 Top-Of-The-Poops

Some data reproduced under Open Government Licence

Please don't scrape these pages - we can maybe share our data with you

Full Copyright information available at: our GitHub page