Water leak repair in London
Some leaks are easy to see and just as easy to put off: a joint under the sink leaving a damp ring in the cupboard, a radiator valve with a green crust round it, an overflow dribbling down the outside wall. They rarely get better on their own. Ninja Plumbers isolates the supply, works out what kind of joint or fitting has failed, repairs it properly, and watches it under full pressure before the cupboard is packed back up.
- Fully insured and Gas Safe registered
- Engineers DBS-checked
- 24/7 emergency callouts
- Price agreed before we start
- Workmanship guaranteed
Monday – Sunday, 7:00 AM – 10:00 PM · Out-of-hours emergency? Call 020 3576 5825
Get a price for leak repair
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Included in the job
- Dripping joints under sinks, basins and baths
- Weeping stopcocks, isolation valves and gate valves
- Radiator valves and radiator tails
- Washing machine and dishwasher hoses and valves
- Compression, soldered and push-fit joints
- Wastes and traps leaking under sinks and baths
- Overflow pipes dripping outside the house
Read this before you ring
You may find you can sort some of this yourself, without calling us. We are fine with that, and would rather you knew it.
Turn it off at the nearest valve
Most sinks, toilets and appliances have a small valve on the pipe feeding them, and closing it stops the leak without cutting water to the whole house. On a radiator, close both valves, counting the turns on the one under the plastic cap so it can be reset. If there is no local valve, use the stopcock. Then dry the pipework, because water runs along a pipe and drips from its lowest point, not from the leaking joint.
The fix depends on the joint
A compression fitting — a nut squeezing a brass ring called an olive onto the pipe — can sometimes be cured with a small nip, but a crushed olive has to be replaced. A soldered joint cannot be tightened; the pipe is drained and the joint remade. A push-fit joint usually leaks because the pipe was not pushed fully home or its end was scored, so it is cut back and remade. Threaded connections need fresh sealing or a new fibre washer.
Leaks that only happen when water drains
If the cupboard only gets wet when the sink empties, the leak is on the waste, not the supply. Fill the bowl, pull the plug and watch. Plastic trap nuts should be firm by hand, and the washers inside flatten and harden with age. A cracked trap, or a waste knocked out of line by whatever is stored in the cupboard, is just as common.
Washing machines and dishwashers
Fill hoses perish from the inside, and one that is stiff, cracked or swollen near the ends should be replaced before it splits. The valve it screws onto can weep at the spindle too. If water appears only when the machine empties, look at the waste hose and the standpipe or trap it runs into. Moving or adding connections is covered on our washing machine plumbing page.
Radiator valves
A radiator valve weeps either from the spindle under the head or from the nut joining it to the radiator. The first can sometimes be cured by gently tightening the gland nut; the second usually means draining the radiator and remaking the joint or fitting a new valve. Heating water is black, so floors get covered first. And every weep on a sealed system costs pressure — a boiler that keeps needing topping up is a reason to check the valves.
An overflow pipe dripping outside
A small pipe through an outside wall is an overflow. It drips when a float valve inside has stopped shutting off — usually on a toilet cistern, a cold water tank in the loft or the small heating tank beside it. Follow the pipe back to find which. If the water is warm, it is coming from the heating or hot water side and wants looking at soon; on an unvented cylinder it can mean a safety valve is opening.
What we check before we leave
The water goes back on slowly, and the repaired joint is dried and watched at full pressure. We look at the fittings either side, since a valve that has started weeping often has a neighbour of the same age not far behind, and at what the leak has soaked: a swollen cupboard base, damp boards, a mark on the ceiling below. If water has already come through downstairs, our water through the ceiling page covers what to do first.
What changes the price
A leak repair is priced on what is leaking and what is in the way. A dripping joint under a sink and a pipe buried beneath a tiled floor can be the same fault but very different jobs.
Whether the source is already known
If the leak can be seen, the engineer goes straight to repairing it. If there is only a stain, a wet floor or a rising meter, the source has to be found first, and that tracing is a separate piece of work.
A fitting, or the pipe itself
Many leaks are at a fitting: a washing machine hose, a radiator valve, a compression joint, a toilet connector. Those are small parts. A split or corroded pipe needs a section cut out and replaced, which takes longer.
Supply, heating or waste
A supply pipe leaks all the time and can be isolated at the stopcock. A heating leak may mean draining and refilling the system. A waste leak only shows when something drains, and is often a loose trap or a failed seal.
The damage it has already done
Fixing the leak stops more water getting out. Drying out a soaked floor, replacing swollen kitchen plinths or laminate, and repairing a stained ceiling are separate from the plumbing repair, and may be covered by your home insurance.
We agree the price with you before any work begins, and accept both card and cash.
Questions we often get
Can I just tighten the nut myself?
On a compression fitting, a small nip — a quarter turn at most, holding the fitting still with a second spanner — sometimes stops a weep. If it does not, stop there: more force crushes the olive and turns a drip into a proper leak. Do not try it on push-fit or soldered joints.
Is a slow drip worth calling someone out for?
Yes, though not as an emergency. A drip on a supply pipe runs day and night, and in a cupboard it rots the base and feeds mould long before anyone sees a puddle.
Will the water be off to the whole house?
Only if there is no working valve near the leak. Where one is missing or seized, we can fit a new one while we are there, which makes the next repair simpler.
The pipe itself has split. Is that this page?
No. A split or burst pipe, often from frost or corrosion, is covered on our pipe repair page. If water is pouring out right now, turn the stopcock off and see our emergency plumbing page.
What about a dripping tap or a leaking toilet?
Both have their own pages, because the fault is usually a part inside the fitting rather than a joint on the pipework. See tap repair and replacement, and toilet repair.
Do you repair leaks on the heating as well?
Yes — radiator valves, radiator tails and visible joints on heating pipework. A leak from inside the boiler casing is a boiler repair, and that needs one of our Gas Safe registered engineers.
Other plumbing jobs we do
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Emergency Plumbing
For burst pipes, serious leaks or a house with no water. The phone is answered at any hour and an engineer is sent out.
Read about Emergency Plumbing -
General Plumbing
Radiators, pipework, taps and toilets: the small jobs that keep getting put off.
Read about General Plumbing -
Leaking Ceiling
Water dripping or pouring through a ceiling. What to do first, then the source found and stopped — in your home or the flat above.
Read about Leaking Ceiling -
Leak Detection
Acoustic and thermal equipment to trace hidden leaks before any floor is lifted.
Read about Leak Detection -
Toilet Repair
Toilets that will not flush, keep running, fill slowly or leak onto the floor. Usually one worn part, replaced without needing a new toilet.
Read about Toilet Repair -
Tap Repair and Replacement
Dripping, stiff and leaking taps repaired, and tired ones swapped for new.
Read about Tap Repair and Replacement -
Pipe Repair
Burst, split, frozen and corroded pipework repaired — or replaced where patching it would be pointless.
Read about Pipe Repair -
Low Water Pressure
Weak taps and showers diagnosed by testing, not by swapping parts and hoping.
Read about Low Water Pressure -
Lead Pipe Replacement
Old lead supply pipes replaced with new, from the boundary into the house.
Read about Lead Pipe Replacement -
Commercial Plumbing
Plumbing for offices, restaurants, shops and blocks of flats, timed to fit the hours you open.
Read about Commercial Plumbing -
Gas Safety Certificates
Your landlord gas safety certificate, checked and issued by a Gas Safe registered engineer and emailed over the same day.
Read about Gas Safety Certificates -
TMV Servicing & Testing
Thermostatic mixing valves tested, cleaned and reset, with a record for every valve, for schools, nurseries, care and business premises.
Read about TMV Servicing & Testing
Looking for leak repair in London?
Tell us what is wrong and where you are, and you will have the price before any work begins.