Sump pump installation and repair for London basements, lower-ground bathrooms, and utility rooms where the waste line sits below the public sewer and gravity will not do the job.
Anywhere in London below the gravity-flow line of the public sewer needs a pump to lift wastewater up to the foul drain. That covers basement flats, lower-ground bathrooms in converted Georgian terraces, garden-level utility rooms, and the lower floor of the thousands of new-build basement conversions in Lambeth, Westminster, and Hammersmith. Without one, every flush, every shower, and every sink discharge backs up into the room it just came from.
Sump pump basement flood prevention is now a near-universal requirement for any property below street level. Most London boroughs also require backflow protection at the basement level as part of planning consent.
We install and repair the brands most London specifiers reach for:
- Saniflo Sanipack, Sanispeed, and Sanibest Pro for kitchen-sink and bathroom-grouping installs
- Stuart Turner Wasteflo for whole-basement collection
- Jung Pumpen Compli sets for larger and commercial flows
Simplex (single-pump) units are normal in residential bathrooms. Duplex (two-pump alternating) is the right call for high-flow commercial, multi-occupancy, or any installation where downtime is unacceptable.
Float-switch failure is the most common fault we are called out to, normally caused by wet wipes or grease binding the pivot. Non-return-valve failure is second. Fluid runs back into the chamber after the pump stops, the pump cycles again, and the duty count climbs until the motor burns out.
For resilience we fit a battery-backed pump pair so a power outage does not equal an overflow. We also fit a high-water alarm with text or email notification, useful for landlords with basement flats they do not live in.
Where the borough requires it (Lambeth, Westminster, and Hammersmith are usually strict), we fit a BS EN 13564 Type 2 anti-flood backflow valve upstream of the sump. This stops a public-sewer surcharge pushing back into the basement during a heavy storm.
Where this service applies
- New basement bathroom, kitchenette, or utility room below the public sewer line
- Lower-ground en-suite or shower room in a converted Georgian or Victorian terrace
- Existing pump cycling repeatedly or running continuously (float or NRV fault)
- Sump overflow with sewage backup into the basement
- Commercial and multi-occupancy sites needing duplex resilience
- Battery-backed backup pump for power-outage flood resilience
- High-water alarm with text or email notification for landlord-managed flats
- BS EN 13564 Type 2 backflow valve required by Lambeth, Westminster, or Hammersmith consent
How we deliver
No surprises, no upselling. The exact path every job follows.
- 1
Site survey and sizing
We measure the lift height to the foul drain invert, the horizontal run, and the inlet flow rate per appliance, then size a Saniflo, Stuart Turner, or Jung Pumpen unit against the manufacturer pump curve. - 2
Simplex or duplex specification
Residential bathrooms normally take a simplex (single-pump) install, commercial and multi-occupancy take a duplex (two-pump alternating) set so a fault on one pump never means downtime. - 3
Sump chamber and pump install
Below-floor sump set on a level base or wall-mount unit sited per manufacturer guidance, inlets through purpose-cut entry seals, discharge run in 32mm or 40mm rigid pipework with smooth bends only. - 4
Non-return valve and isolation
Spring-loaded NRV on the discharge above the sump to prevent backflow once the pump stops, isolation valve above the NRV so the pump can be serviced without draining the rising main. - 5
Backflow protection upstream
Where the borough requires it (Lambeth, Westminster, Hammersmith are usually strict), a BS EN 13564 Type 2 anti-flood valve is fitted upstream of the sump to stop a public-sewer surcharge. - 6
Alarm and battery backup
High-water alarm wired to a sounder and a text or email notification module, and where specified a battery-backed secondary pump that takes over during a power cut. - 7
Commissioning and handover
Run-test on every connected appliance, float-switch range checked, NRV proven, alarm tested, customer walked through the manual rinse-cycle. Service schedule logged.