Septic tanks & sewage · London

How much does Septic tanks & sewage cost in London? (2026 price guide)

Emptying a standard domestic septic tank typically costs £150-£300, with most households needing this done once a year or so. Servicing or repairing a sewage treatment plant generally runs £150-£400 for routine maintenance, while a full tank replacement or new installation usually costs £3,000-£7,000 depending on ground conditions and tank size.

Costs depend mainly on tank size and accessibility for the tanker, how often the system has been serviced previously, whether pumps or mechanical parts need replacing, and local disposal charges for waste. Systems that have been neglected for several years often need a more thorough clean and inspection, adding to the price.

Setting up a regular annual emptying and servicing contract tends to be cheaper overall than waiting for an emergency callout when a system fails.

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