If sewage is coming out of a manhole in your garden, drive or path, treat it as a drainage problem that needs prompt attention. The overflow may be caused by a blockage on your property, but it could also involve a public or shared sewer. Paying someone to clear the wrong section of drain can be an expensive mistake.
First, reduce the risk of more sewage escaping
Stop flushing toilets and running appliances connected to the affected system where practical. Keep children, pets and visitors away from the affected area. Avoid splashes and contact with wastewater; sewage can contain harmful microorganisms. Do not attempt to enter the chamber or reach into it.
If sewage is approaching a doorway, air brick or electrical installation, put personal safety first. Avoid handling electrical equipment in wet or contaminated areas. Where flooding presents an immediate danger, seek urgent assistance from the appropriate emergency service.
Make a note of the time and photograph the situation from a safe distance. These details can help a sewerage company, contractor or insurer understand what occurred.
What does a rising manhole tell you?
A manhole or inspection chamber gives access to underground pipework. When water cannot pass a downstream obstruction, it can back up and rise through the chamber. That obstruction might be a build-up of waste, a root intrusion, a displaced joint or, less commonly, a seriously damaged pipe.
Heavy rain can make matters worse, particularly where rainwater enters the same drainage network. But the fact that sewage overflows during a storm does not prove the drain is simply too small. A partial blockage may have been present beforehand.
Do not assume that an overflowing chamber is directly over the fault. The restriction can be farther downstream.
Should you call the water company?
Yes, if a public or shared sewer might be involved, contact your sewerage provider promptly. In England and Wales, sewerage companies generally maintain public sewers and adopted shared sewers, even where some run beneath private land. Private drains serving only one property within its boundary normally remain the homeowner's or landlord's responsibility.
Neighbours reporting similar symptoms, or more than one property draining into the affected section, may suggest that a shared sewer is involved. They are clues, not a substitute for checking ownership. Your provider can advise on its records and responsibilities.
See Ofwat's guidance. In other UK nations the arrangements may differ.
What if the sewage has entered the house?
Avoid the contaminated area as much as possible. Do not attempt to clean sewage without suitable precautions, and never use electrical appliances standing in floodwater. Notify your home insurer if the building or contents are affected, and follow its instructions about evidence, cleaning and repairs.
If the flooding involves the public sewer, report it to the sewerage company as well. Ask for a reference number and keep a record of conversations. The Consumer Council for Water explains how complaints about sewer flooding can be taken further.
What a drainage specialist should establish
For a privately maintained drain, a contractor may clear the obstruction and check the line is running freely. If the blockage keeps returning, ask for evidence of why. Camera footage may identify a fractured pipe, persistent root intrusion or an offset joint that needs targeted work.
Before authorising excavation, ask exactly where the defect lies, how it was located and whether a less disruptive repair is suitable. A verbal assertion that the pipe has collapsed is not enough to justify a large repair bill.
After the overflow has stopped
Check that connected fixtures discharge without causing water to rise in the chamber. Arrange safe, appropriate cleaning of contaminated areas and keep a record of any damage. If the blockage was in a private drain, request an explanation of what was removed and whether further inspection is recommended.
If this has happened before, read why drains keep blocking. If water is also coming up through an indoor fixture, see sewage backing up through the shower.
Need a local drainage contractor?
If the blockage appears to be in a privately maintained drain, you can request quotations from drainage specialists through MyJobQuote. Explain whether sewage is overflowing, how long the problem has been present and whether the drain has already been cleared.