Open data for everyone who cares about our rivers
WaterWatch monitors every Combined Sewer Overflow (CSO) discharge event in the Thames Water region in real time. Our platform processes raw data directly from Thames Water's Event Duration Monitoring (EDM) network and presents it in a clear, accessible format — so anyone can see exactly when and where overflows are occurring.
We're on everyone's side. Whether you swim, fish, row, or simply care about clean rivers, we give you the same information that regulators, water companies, and communities use — presented simply, without spin. We celebrate real progress too: where Thames Water sites have genuinely improved year on year, WaterWatch shows that clearly alongside the sites that still need attention.
Transparent data is the most powerful tool for informed conversation. When everyone can see the same picture, communities, regulators, and water companies can work together toward cleaner rivers.
Sourced directly. Never spun.
All discharge data is sourced directly from Thames Water's public Event Duration Monitoring API. We do not modify, smooth, or summarise any readings — what you see is exactly what Thames Water's own EDM network reports.
River level data is sourced from the Environment Agency's real-time monitoring network. Rainfall data comes from EA-registered gauging stations nearest to each CSO site.
We'd love to extend WaterWatch to Severn Trent, Southern Water, Yorkshire Water, and the rest — but most water companies don't yet publish a real-time API that includes historical discharge data. Thames Water is currently one of the few that offers this level of openness, and we're grateful for it. As other companies improve their data transparency, we'll be ready to bring them onto the platform.
Have a question or idea?
We'd love to hear from you. Whether it's feedback, a media enquiry, or a data request — get in touch.
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