Drains in a block of flats are usually shared. Waste from several flats joins a common soil stack and underground drain before reaching the sewer, so a blockage in one place can affect several homes. Who is responsible depends on where the blockage is and what the lease says.
Start with the lease
For leasehold flats, the lease sets out who is responsible for what. Typically:
- Pipes that serve only your flat, such as the waste from your sink or the pipe from your toilet to the shared stack, are often the leaseholder’s responsibility.
- Shared pipes, such as the soil stack, shared underground drains and gullies serving the building, are often the freeholder’s or management company’s responsibility, with the cost recovered through the service charge.
Leases vary, so check yours or ask the managing agent.
Where is the blockage?
- Only one fitting in your flat is affected: the blockage is probably in the pipe serving that fitting.
- Several fittings in your flat are affected: the blockage may be where your pipes join the shared stack.
- Ground floor flats are flooding, or several flats are affected: the blockage is likely in the shared stack or the underground drain. Ground floor flats are often hit first because waste from above backs up at the lowest point.
If you rent the flat
Tell your landlord or letting agent straight away. Landlords are usually responsible for keeping drains and waste pipes in repair, unless the blockage was caused by misuse. See blocked drains in rented properties.
If it is an emergency
If sewage is backing up into a flat:
- Stop using water, and ask neighbours above to stop too.
- Contact the managing agent or freeholder’s emergency line.
- If you cannot reach anyone and it is getting worse, a drainage company can attend. Keep records and photos for any claim.
See what to do if a drain overflows.
Beyond the building
Drains that leave the building and serve other properties may be public sewers, which are the water company’s responsibility. See who is responsible for a shared drain.
For managing agents and freeholders
Blocks with repeated blockages often benefit from planned cleaning of the stacks and underground drains, and a camera survey to find defects. A simple notice to residents about what not to flush helps too; see can you flush wet wipes?
We work with managing agents, landlords and residents. See drain unblocking and commercial drainage.