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Area of Outstanding Natural Beauty

Chilterns - Live Sewage

Polluted by sewage 56 hours in 2026 so far..

© OpenStreetMap contributors
Contains OS Data © Crown copyright & database right 2021-2024
© Top of the Poops 2021-2024

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Totals for 2026

Sewage56 hours
Monitoring offline0 hours
Potential pollution0 hours
Storm overflows14

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Daily Data - when it rained, and when they spilled

Square = rainfall none → heavy
Drop = sewage minutes → all day
Potential pollution Monitoring offline
Jan - 27 hours
Feb - 26 hours
Mar - 3 hours
Apr - 0 hours
May - 0 hours
Jun - 0 hours
Jul - 0 hours
Aug - 0 hours
Sept - 0 hours
Oct - 0 hours

Storm overflows in and around Chilterns

Company Site Name Receiving Waterway Overflow Days Total Duration (hours) Offline/Potential Pollution
Thames Water Dagnall STW Groundwater Via Infilt System 7 22h 30m -
Thames Water Watery Lane (Marsworth) SPS Tring Bourne 12 19h 15m -
Thames Water Berkhamsted STW Grand Union Canal 3 12h 15m -
Thames Water Hambleden STW River Thames 2 2h -
Thames Water Tring STW Into Guc/Reservoir 1 0h 30m -
Thames Water Chesham STW River Chess 0 0h -
Thames Water Amersham balancing tanks/amersham vale stk Misbourne 0 0h -
Thames Water Dagnall STW Groundwater Via Infilt System 0 0h -
Thames Water Sonning Common STW Into Land 0 0h -
Thames Water Hambleden STW River Thames 0 0h -
Thames Water Chesham STW River Chess 0 0h -
Thames Water Amersham balancing tanks/amersham vale stk Misbourne 0 0h -
Thames Water Berkhamsted STW Grand Union Canal 0 0h -
Thames Water Sonning Common STW Into Land 0 0h -

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.