Surface water flooding — caused by heavy rainfall overwhelming drainage systems rather than rivers overflowing — affects hundreds of thousands of properties in England each year. Greater Manchester, with its high annual rainfall, clay-heavy soils, and extensive Victorian combined sewer network, is one of the areas most exposed.
Unlike river flooding, surface water flooding can happen almost anywhere, often with little warning. This guide explains how the system works, what to do when it fails, who is responsible for fixing it, and practical steps to reduce your risk.
How Surface Water Flooding Happens
When rain falls, it either soaks into the ground (infiltration) or runs off into surface water drains, gutters, and eventually the sewer network. Manchester’s predominantly clay and silt soils have low permeability — water soaks in slowly, so a high proportion runs off into the drainage system.
Manchester’s Victorian combined sewer system carries both surface water and foul (sewage) water in the same pipes. During heavy rainfall, this system is easily overwhelmed, causing:
- Water rising through surface water gullies
- Manhole covers lifting under pressure
- Sewage and surface water backing up into properties through ground-floor drains
A single hour of intense rainfall — 20mm or more — is enough to cause surface water flooding in parts of Manchester. Climate projections suggest these intense rainfall events will become more frequent.
Immediate Steps During Surface Water Flooding
At the First Sign of Water Rising
- Move valuables, electrical equipment, and important documents upstairs or to high shelves immediately
- Turn off electricity at the fuse box if water is approaching floor level — do not touch switches if standing in water
- Move your car to higher ground if safe to do so
- Do not attempt to walk or drive through fast-moving flood water — it is dangerous even at shallow depths
Limiting Water Entry
- Place sandbags or flood barriers at external doors if you have them
- Stuff towels or draught excluders against door bases as a temporary measure
- If you have airbricks, block them temporarily with purpose-made covers or bags
- Close all internal doors to slow water spread
Once Water Stops Rising
- Document everything with photos and video before any clean-up
- Call your insurer and our emergency drainage team on 0161 282 8080
Who Is Responsible for Surface Water Flooding?
Responsibility is split across several organisations, which makes it frustrating to navigate.
| Drainage type | Responsible body |
|---|---|
| Private drain within your property | You |
| Public sewer (shared or lateral) | United Utilities |
| Surface water drain connecting to public sewer | United Utilities |
| Ordinary watercourse (small streams, ditches) | Local authority or riparian owner |
| Main river | Environment Agency |
| Highway drainage | Transport for Greater Manchester / local authority |
United Utilities: 0345 672 3723. Report sewer flooding — they have a duty to investigate.
Manchester City Council / your local authority: Report highway flooding or ordinary watercourse problems.
Environment Agency: Flood warnings, river levels, and major flood events.
When Is It a Drainage Problem You Can Fix?
Not all surface water flooding is caused by the public network failing. Sometimes the issue is within your own drainage:
- A blocked surface water gully preventing rainwater leaving your driveway or garden
- A downpipe disconnected from the underground drain, causing water to pool against the building
- A full or blocked soakaway that no longer absorbs surface water
- A partially blocked private drain that can’t handle heavy rainfall
A CCTV drain survey identifies whether the problem is in your private drainage, and drain jetting clears any blockages that are contributing to the flooding.
Longer-Term Measures to Reduce Flood Risk
Non-Return Valves
Fitted to drain connections, non-return valves allow water to flow out but prevent it flowing back in. They are particularly effective at preventing sewer flooding entering properties through ground-floor drains and toilets during extreme rainfall events. We can supply and fit these — call 0161 282 8080 for a quote.
Permeable Paving
Replacing impermeable driveways and patios with permeable surfaces reduces run-off from your property into the combined system.
Water Butts and Rain Gardens
Capturing rainwater from roofs reduces the peak demand on the drainage system during storms.
Check Gutters and Downpipes Annually
Blocked gutters are a major source of surface water that enters the drainage system in concentrated bursts. Keep them clear.
Cleaning Up After a Flood
Surface water flooding often contains sewage. Treat all flood water as contaminated:
- Wear gloves and waterproof footwear
- Do not eat, drink, or smoke during clean-up
- Disinfect all hard surfaces with bleach-based products
- Bag and dispose of soft furnishings that cannot be disinfected
- Run a dehumidifier for several days — damp structures promote mould
Insurers will want a drainage survey report if the flooding came from drains. We provide these as standard.
Call 0161 282 8080 for emergency drainage assistance and post-flood assessments anywhere in Greater Manchester, including Manchester, Salford, Bury, Rochdale, Bolton, Wigan, and Stockport.
Frequently Asked Questions
United Utilities say the flooding is from my private drain. What do I do?
Commission an independent CCTV drain survey to confirm whether the fault is in your section of pipe. If the survey shows the fault is in United Utilities’ network, you have documented evidence to challenge their position.
Can I claim on my insurance for surface water flooding?
Most standard buildings insurance policies cover sudden, unexpected flood damage. Check whether your policy specifically excludes surface water flooding — some do. Take photos before any clean-up and get a drainage engineer’s report.
How do I know if my area is at risk of surface water flooding?
The Environment Agency’s flood map for surface water is publicly available. Search “flood map for planning England” to find it. It shows low, medium, and high surface water flood risk by postcode.