Harpenden and Berkhamsted was polluted by sewage 427 times in 2024
lasting 5,999 hours

Constituency

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✔ means we have experimental daily data since 2023

Live data for Harpenden and Berkhamsted in 2025

So far this year (as of Apr 16, 2025, 5:30 PM) there has been 2,872 hours of sewage overflows

Totals for Harpenden and Berkhamsted in 2024

7 Sites polluted by Thames Water

427 sewage dumps
5,999 h duration

That's 8.33 months. On average 1.2 times a day

Change Over Time

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Constituencies near Harpenden and Berkhamsted

Waterways in Harpenden and Berkhamsted

Daily Data

We get information about overflowing CSOs since January 2025. Here is a chart of the last three months of data for Harpenden and Berkhamsted, here you can see overflows in red, the darker the red, the more the CSO overflowed that day.

Each CSO has a row, the most recent data is on the right hand side.

Monitoring Online Monitoring Offline Polluting Potentially Polluting Unknown

Daily data is experimental and data is not guaranteed to be accurate. Please inform us of any issue, we will fix.

Pollution Summary 2024

Here are all the reported sewage overflow totals for Harpenden and Berkhamsted in 2024. Sometimes sewage can be being dumped for months at a time.

Reporting refers to how much of the time the monitoring was active. In this constituency 0 of the total 7 CSO locations had reporting enabled for less than half the year, of which 0 had zero reporting.

Company	Waterway	Site	Sewage Dumps	Duration (Hours)	Reporting %
Thames Water	River Ver	MARKYATE WASTEWATER TREATMENT WORKS	187	3,383	99.8
Thames Water	Grand Union Canal	BERKHAMSTED SEWAGE TREATMENT WORKS	157	1,775	100
Thames Water	Gw Via Boreholes	CADDINGTON WWTW	32	372	99.9
Thames Water	Lee	Harpenden	32	352	100
Thames Water	River Lee	WHEATHAMPSTEAD PUMPING STATION , HE	12	87	90.6
Thames Water	River Bulborne	Trumps Green	5	21	100
Thames Water	Into Guc/Reservoir	Tring (2m - Main Outfall)	2	6	94.5

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. This 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

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