Southampton has many streets of Victorian and Edwardian terraced houses, in areas such as Shirley, Freemantle, St Denys, Portswood, Bevois Valley and Polygon. Their drains are often more than a century old and laid out differently from modern homes, which affects both what goes wrong and who is responsible.
How terrace drains are often laid out
- Shared runs behind the houses. In many terraces, each house’s drain joins a single pipe that runs behind or beneath several gardens before reaching the sewer in the road.
- Drains under the house. Some run under the house to the front, especially in mid-terrace properties without rear access.
- Clay pipes. Original drains are usually salt-glazed clay with short sections and many joints.
- Interceptor traps. Many have an interceptor trap in the last chamber. See what is an interceptor trap?
Who is responsible?
This is the question we are asked most about terraces. Since October 2011, most shared drains and lateral drains connected to the public sewer before 1 July 2011 became the responsibility of the water company. In practice:
- The pipe serving only your house, within your boundary, is usually yours.
- The shared run behind several houses is usually a public sewer, and the water company’s responsibility, even though it runs through private gardens.
See who is responsible for a shared drain and blocked drain: Southern Water or me?
Common problems
- Root ingress through clay joints, especially where trees grow in back gardens. See tree roots in drains.
- Displaced and cracked joints after a century of ground movement.
- Blockages at interceptor traps, particularly when the stopper is lost.
- Rats, which can use defects in old drains. See rats in drains.
- Building work, such as rear extensions, built over or close to shared drains. See building an extension over a drain.
Diagnosing problems in a terrace
Because drains are shared, a blockage may be in your pipe, the shared run or the sewer. Checking chambers, asking neighbours and, where needed, a CCTV drain survey shows exactly where the problem is and who should deal with it, so you do not pay for work that is not your responsibility.
Buying a terraced house
A drain survey before buying shows the route, condition and any shared sections. See drain surveys before buying a house.
If you have a blocked drain in a terrace, see blocked drains in Southampton.