Original research · FOI & EIR
Original research and data reports from Drainage & Plumbing Ltd, built from official records we obtain directly from water companies and councils under Freedom of Information and Environmental Information Regulations requests, alongside published public datasets.
Why we publish this
When a drain backs up, the first question a homeowner asks is whether it is their problem or the network’s. That answer is usually recorded somewhere — in a water company’s incident log or a council’s callout data — but it is rarely published in a form anyone can read. We request those records, clean them up, and publish them in full, including the parts that are inconvenient for us.
What separates these from a blog post:
- Every figure comes from a named source we can point you to, not from an industry estimate.
- Where a report comes from a request, its reference number and response date are published with it, so you can request the same records yourself; where it comes from an already-published dataset, we name the dataset and the year it covers.
- Where a dataset is incomplete or a body refused part of a request, we say so in the methodology rather than filling the gap.
Published reports
Blocked gullies
Blocked Gullies Across Surrey: The 2022–2025 Council Data Report
Every report the public made to Surrey County Council about a blocked gully, a blocked drain or highway flooding over three years — 18,463 of them, mapped by street, town, ward and month. Just 477 streets account for 45% of the total.
Spills & flooding
Sewage Spills & Sewer Flooding Across South London & Surrey: 2022–2025
Where storm overflows spilled sewage into rivers in 2025, and where the sewer network flooded homes and gardens over the three years to March 2025 — 250 spills, 1,578 hours of discharge, and 420 flooding incidents, up 61.5% since 2022/23. Croydon carries the heaviest load of any postcode district.
How we obtain the data
1
We identify which body actually holds the record — a water company for sewer incidents, a highway authority for gully and road drainage.
2
We submit a request under the Environmental Information Regulations 2004, or the Freedom of Information Act 2000 where the body is a public authority.
3
We publish the response as received, note any refusals or exemptions applied, and keep the reference number on the report.
Not every report needs a request. Where a regulator already publishes the underlying record — as the Environment Agency does for storm overflow monitoring — we use the published dataset directly and say so in the report, rather than asking for data that is already in the open.
Corrections
If you hold data that contradicts anything published here — particularly if you work for one of the bodies whose records we have used — tell us and we will correct the report and say what changed. Get in touch.
Worried about a drain on your property?
Network-wide data tells you what is normal for your area. It does not tell you what is happening in your own pipe. If a drain is backing up, an engineer can put a camera down it the same day.