Drainage Services in Greater London

Their main customer line is 0800 980 8800. Parts of north-east London (Romford, Hornchurch and Upminster) fall under Essex & Suffolk Water for water supply, and parts of outer west London are covered by Affinity Water — sewerage in both cases stays with Thames Water. Check the Ofwat boundary map for the exact split at your postcode.

Source: dwi.gov.uk

The headline rule still holds — Thames Water owns and maintains public sewers and lateral drains past the property boundary; anything inside the boundary is the homeowner's or landlord's. But many inner-borough terraces sit on shared drains that were private before 2011 and adopted afterwards, so freeholders sometimes still believe they're liable for a run that's now Thames Water's problem. North-east boroughs around Romford, Hornchurch and Upminster sit in the Essex & Suffolk Water area for water supply (sewerage stays with Thames Water), and outer-west postcodes around Hayes, Uxbridge and Watford fall under Affinity Water for supply only. Citizens Advice publishes the canonical consumer-facing summary if a dispute escalates.

Source: citizensadvice.org.uk

A like-for-like patch is usually exempt, but a building notice or full plans submission is needed if you're re-routing a drain, replacing a long section, or altering the connection into a public sewer. Older London housing stock (especially Victorian terraces in inner boroughs) often hides shared drains running between properties — confirm boundaries with your local council building control before work starts.

Source: planningportal.co.uk

London's huge outer-ring LCC and GLC estates built between roughly 1950 and 1975 — Becontree's later extensions, the Roehampton Alton Estate, Lansbury in Poplar, parts of Thamesmead — used pitch fibre extensively. Inner-borough Victorian and Edwardian terraces almost never have it (they predate the material), while post-1980 redevelopments use uPVC. The signature symptom is a drain that blocks within days of being jetted clear: the coal-tar-impregnated pipe has gone oval and the run no longer self-cleanses. A CCTV survey confirms it within minutes. Re-rounding plus a cured-in-place liner is the no-dig fix; full excavation is needed where the pipe has collapsed or fractured at a joint.

Source: sava.co.uk

Read more on our blog: /blog/do-you-have-pitch-fibre-pipes/

Many of the 19th-century brick combined sewers — including Bazalgette-era intercepting runs — sit deeper, larger and less accurately mapped than the modern record shows. Thames Water still applies the standard 3-metre proximity rule (1 metre for a lateral drain), but in inner boroughs the surveyor should treat the asset record as a starting point, not the truth, and trace the line with sonde tracking before any spec is signed off. Apply via Thames Water Developer Services well ahead of works: Class 1 and 2 cases (sewers 375mm and under) typically close in around three months, while Class 3 (sewers 375mm or larger) needs a formal legal agreement and can run nine months or longer per Thames Water's published timing. Skipping the agreement on an un-mapped sewer is the headline risk — if Thames Water later needs access for repair, the homeowner pays to remove footings.

Source: thameswater.co.uk