If you’ve noticed water pooling around a manhole cover, or worse, water and waste overflowing from one, it’s a clear sign that something further down the drainage system is blocked. Manholes are inspection and access points for the network beneath them, and when they back up, it usually means the blockage is significant.
What causes a manhole to back up
A manhole sits at a junction or change of direction in the drainage system, which makes it a natural point for debris to collect. Common causes include a build-up of fat and wipes further down the line, root ingress from nearby trees, a collapsed or displaced section of pipe, or simply a large volume of debris being carried into the system after heavy rain.
Why it’s a safety issue, not just an inconvenience
A blocked or overflowing manhole isn’t just unpleasant. Foul water contains bacteria and contaminants that pose a genuine health risk, and a manhole cover itself can become a hazard if it’s been lifted or displaced by pressure building up underneath. This isn’t a situation to deal with by lifting the cover and having a look yourself.
What to do if you find one
- Keep people and pets away from the area, particularly children
- Don’t attempt to lift the cover or clear debris by hand
- Avoid pouring anything down nearby drains while the system is backed up
- Note whether the manhole is on your property, a shared area, or a public road, as this affects who’s responsible
If the manhole is on a public road or affects the wider sewer network, it may be a case for the water company rather than a private contractor. Our guide on who to call for a blocked drain explains how to tell the difference.
How a professional clears it
Our engineers use CCTV equipment to see exactly what’s causing the blockage before recommending a fix, whether that’s jetting, rodding, or in more serious cases a full drain survey to check for structural damage further along the run.
If you’ve spotted a blocked or overflowing manhole, don’t wait for it to get worse. Call us on 0333 200 1623 and we can get someone out to assess it properly.