Groundwater

Sump pump installation in London

London clay holds onto water, so a basement sitting below the water table is going to take some in no matter what the walls are built from. A sump chamber with a pump gives that water somewhere controlled to collect and a controlled route back out again, rather than letting it find its own way across the floor. Ninja Plumbers installs these systems, replaces the ones that have failed, and services units already sitting quietly under a cover most homeowners have never once lifted.

  • Gas Safe registered and fully insured
  • DBS-checked engineers
  • Emergency callout available 24/7
  • Price agreed before work starts
  • Workmanship guaranteed

Monday – Sunday, 7:00 AM – 10:00 PM · Out-of-hours emergency? Call 020 3576 5825

Get a price for sump pumps

Three details get an engineer moving. The rest is optional.

How urgent is it?
Add address or details optional

Or call 020 3576 5825 WhatsApp +44 7447 575645

We only use these details to deal with your enquiry. Privacy policy

What we cover

What's included

  • Sump chamber and pump installation
  • Replacing failed or undersized pumps
  • Dual-pump systems and battery backup
  • Discharge pipework and non-return valves
  • Float switch faults and high-water alarms
  • Annual testing and servicing
Before you call

Worth knowing first

A bit of this might save you from needing a callout at all — we'd rather you knew it upfront.

A sump pump is not a damp-proofing system

It manages water that gets in. It does not stop it getting in. If the basement is being converted into living space, the pump is one part of a tanking and drainage design, not a substitute for one.

One pump is one point of failure

Rely on a single pump in a basement nobody checks daily, and the water itself is usually how you find out it has stopped working. Adding a second pump set on a higher float switch, or at the very least a high-water alarm, is a small extra cost against the damage it prevents.

Where the water goes matters legally

Groundwater should not be discharged into the foul sewer. It needs to go to a surface water drain or a soakaway, and getting that wrong can land you with a bill from the water company rather than a fine from anyone else.

Test it before the wet season, not during it

Pour a bucket into the sump in September and watch it run. A pump that has sat dry all summer with a stuck float is a very common autumn callout.

Questions

Common questions

Do I really need a backup pump?

If the basement is habitable, storage you care about, or somewhere you cannot check daily, yes. If it is an empty cellar with a concrete floor, an alarm may be enough.

How often should it be serviced?

Once a year, and tested by hand a couple of times besides. Servicing is mostly cleaning the chamber, checking the float travel and confirming the non-return valve still holds.

Can it discharge into the drain outside?

Into a surface water drain, usually yes. Into the foul drain, generally not. Which one you have outside is the first thing we check.

My basement floods in heavy rain. Is a pump enough?

Sometimes yes, but sometimes water is getting in somewhere it genuinely should not, and a pump would only be masking that rather than fixing it. We will tell you honestly which situation you are in, even when the honest answer means a bigger job than just fitting a pump.

Related work

Part of our bathrooms & pumps work

If it turns out to be a repair job rather than a new install, this is where that's covered.

Need sump pumps in London?

Let us know what’s going on and whereabouts you are, and we’ll give you a price before any work starts.