Methodology deep-dives, data journalism, and the occasional opinion piece from the team building WaterWatch. No spin. No paywall. Just the data.
After controlling for rainfall and antecedent wetness, the Witney CSO discharged 24% less frequently per unit of environmental pressure following its October 2025 upgrade — and the after-window was wetter than average, which makes the improvement harder to explain away.
Where the data comes from, how we process it, what the numbers mean, and where our limits honestly lie. Everything we'd want to know if we were reading someone else's sewage tracker.
Thames Water spends billions on infrastructure upgrades. But raw before/after spill counts are almost meaningless without controlling for weather. Here's the pressure-scoring methodology we built to cut through it.
Event Duration Monitoring has transformed how we track storm overflows. But sensors break, signals get lost, and data sometimes needs a raised eyebrow. Here's an honest guide to what EDM can and can't tell you.
Reducing spill hours year-on-year sounds straightforward. It isn't. Rainfall, sensor gaps, and three-year baselines all complicate the picture. Here's our honest framework for reading improvement signals.