DIY GUIDE · PLUMBING & HEATING · CHECKED OCTOBER 2026
How to handle a plumbing emergency yourself
Minutes to stop the water. £10–£25 for a stopcock key and a plunger kept ready.
Water off first, every time. Then the electrics. Then decide whether it is yours to fix or the plumber's.
- Every step, start to finish
- Checked October 2026 — sources at the end
- Honest about when to call a pro
FIRST, THE HONEST ANSWER
Do it yourself, or get a plumber?
Do it yourself if…
- You know where the stopcock is, or can find it quickly, and it turns
- The problem is a toilet that will not stop running or is about to overflow
- A tap will not turn off and has an isolating valve or a working stopcock
- The boiler has lost pressure on a sealed system with a filling link you can find
Get a pro if…
- Water is pouring from a pipe you cannot see, or through a ceiling, and will not stop
- The stopcock is seized, missing or does not stop the water
- There is sewage backing up into the house
- There is any smell of gas, or the problem is inside the boiler or on an unvented cylinder
Safety first
- If water is near lights, sockets or the consumer unit, switch off at the board before going near — but never stand in water to reach the board. HSE's electrical guidance is to isolate first.
- If you smell gas, do not use switches or flames. Open the doors and windows, turn the gas off at the meter lever if you know where it is, leave the house and ring the gas emergency line on 0800 111 999.
- A ceiling holding water can come down. Keep out from under it, put a bucket below, and pierce it from the side with a broom handle.
- Hot water from a burst on the hot side scalds. Turn off the boiler or immersion heater as well as the stopcock.
- Wear gloves for anything involving a toilet or a drain; waste water carries bacteria.
Stop here: Stop here: the mains, the gas side and anything pressurised
Stopping the water, clearing a toilet and topping up a sealed system through its existing filling link are the householder's part. The supply pipe outside the house and the stopcock in the street are the water supplier's or the owner's to repair, and any new water fitting must meet the 1999 Water Fittings Regulations in England and Wales, the Scottish Water byelaws in Scotland or Northern Ireland's 2009 Water Fittings Regulations. An unvented hot water cylinder is covered by requirement G3 and England's Approved Document G, with equivalent rules in Wales, Scotland and Northern Ireland, and only an unvented-qualified installer should work on one. Any work on a gas appliance or its pipework, including the gas side of a boiler, is restricted to Gas Safe registered engineers under the 1998 Gas Safety (Installation and Use) Regulations in Great Britain and the 2004 Regulations in Northern Ireland. How to hire an emergency plumber →
| MATERIAL | COVERAGE | FOR THIS JOB |
|---|---|---|
| Nothing, if the kit is ready | The point is to have it before the emergency | A stopcock key, a plunger and a clamp |
| Emergency pipe repair clamp | Sized to your pipes | One for each size |
| Bin bags and towels | For the clean-up | Plenty |
| Disinfectant | After any toilet or drain emergency | A bottle |
Why the first minute matters
Water lost = flow rate × minutes before the stopcock goes off. A burst running at 15 litres a minute for 10 minutes while you look for the stopcock is 150 litres — a bath and a half, through the ceiling.
Knowing where the stopcock is turns ten minutes into one.
The internal stopcock is usually under the kitchen sink, or where the supply pipe enters the house — sometimes in a downstairs toilet, a cellar, a garage or a cupboard by the front door. Find it, turn it off and on, and label it. In a flat it may be in a communal cupboard or under the bath.
Most houses also have an external stopcock in a small chamber in the pavement or front garden, turned with a long key. If the inside one will not turn, this is your backup. A stopcock key costs little and saves a flood; keep it by the front door.
Most modern taps, toilets and appliances have their own small isolating valve with a screwdriver slot. A quarter turn so the slot sits across the pipe shuts off that one fitting and leaves the rest of the house with water. Know which fittings have them.
A plunger with a soft rubber collar seals in a toilet outlet and clears most toilet blockages. Buy it before the night you need it.
If you have a combi or system boiler, find the filling link and the pressure gauge in daylight. A boiler maker's filling guide we checked sets the normal band at 1 to 1.5 bar. Knowing how to top it up turns a cold house in January into a ten-minute job.
THE PART THAT DECIDES THE FINISH
Before you start — which emergency you have
The first move is the same for most of them: water off. Then find your case.
Water pouring from a pipe or a ceiling
The most urgent case.
- Turn the stopcock off clockwise until it stops
- Switch off the electricity if water is near lights or sockets, without standing in water
- Open the cold taps on the lowest floor to drain the pipes; open the hot taps too if a hot pipe has gone, and turn off the boiler
- Catch the water with buckets and pierce a bulging ceiling from the side
Toilet about to overflow
Do not flush again.
- Lift the cistern lid and push the float down, or close the toilet's isolating valve, to stop more water coming in
- Bail the pan to half full into a bucket
- Plunge with a flange plunger pushed into the outlet
- If it will not clear, or other drains are backing up, it may be the drain outside
Tap will not turn off
A failed washer, cartridge or spindle.
- Close the isolating valve under the tap with a flat screwdriver
- If there is no valve, turn off the stopcock
- Leave the tap open so you can see the water has stopped
- Fix it with the leak repair method, or leave it isolated for a plumber
No heating or hot water, pressure low
A sealed system that has lost pressure.
- Read the gauge with the system cold
- If it is below the green band, top up through the filling link as the boiler's instructions show
- Reset the boiler as its instructions say once the pressure is back
- If the pressure falls again within days, there is a leak — call an engineer
Sewage coming back into the house
A drain blockage downstream.
- Stop using water anywhere in the house
- Lift the nearest inspection chamber cover outside; a full chamber means the blockage is further down
- If the chamber is shared with neighbours, or beyond your boundary, report it to your sewerage company
- Keep children and pets away and wear gloves
THE JOB
What to do, in order
Stop the water
2 minRead the cards above to see which case you have; for most of them, this step comes first. Turn the stopcock clockwise until it stops. If it will not move, do not lever it with a wrench; go to the outside stopcock in the pavement chamber with the key. For a single fitting, close its isolating valve instead and keep water to the rest of the house.
- Clockwise to close, as you look at the handle
- A stopcock that has not been turned for years can stick; firm steady pressure, not a sudden heave
- Shout to the household that the water is off
Mistake to avoid: Spending the first five minutes moving furniture and fetching buckets. The water keeps coming the whole time; the stopcock comes first.
Make the electrics safe
2 minIf water is anywhere near lights, sockets, the cooker or the consumer unit, switch off the main switch at the board — but only if you can reach it without standing in water or touching wet switches. If you cannot, leave the area and tell the emergency plumber and an electrician when you call.
- Use a torch, not the lights, once the power is off
- Do not touch an appliance that is standing in water
- Have wet electrics tested by an electrician before switching back on
Mistake to avoid: Reaching for a light switch in a flooded room. Water and mains electricity together are the danger that kills, not the water alone.
Drain the pipes
5 minOpen the cold taps on the lowest floor to empty the pipes, and flush the toilets once. If a hot pipe has burst, turn off the boiler or immersion heater, then open the hot taps too. The water already in the pipes drains away there instead of through the leak.
- Downstairs taps drain the most water fastest
- A loft tank keeps feeding the hot side; close its outlet valve if you can reach it
- Leave the taps open until the plumber arrives
Mistake to avoid: Turning off the stopcock and stopping there. The pipes above the leak still hold their water, and it all comes out of the burst.
Contain the damage
15 minPut buckets under drips and towels along the floor. Move electrical items, rugs and furniture out of the wet area. If a ceiling is bulging, put a bucket under the lowest point and pierce it from the side with a broom handle, keeping out from underneath. Photograph everything for your insurer.
- Lift rugs before they wick water across the floor
- Take photographs before you start tidying
- Note the time the leak started and when you stopped it
Mistake to avoid: Standing under a sagging ceiling to look at it. A wet ceiling can drop in one piece.
Clear an overflowing toilet
15 minStop the cistern refilling by pushing the float down or closing its isolating valve. Bail the pan to about half full. Push a flange plunger into the outlet so it seals and plunge firmly, keeping it under water. When the level drops suddenly, it has cleared. Test with a bucket of water poured from a height before you flush.
- Gloves on, towels round the base
- A gentle first stroke, then firm ones
- If other drains in the house are backing up, the blockage is outside
Mistake to avoid: Flushing again to see if it has cleared. If it has not, a full cistern goes over the rim.
Stop a tap that will not turn off
10 minClose the isolating valve on the pipe under the tap with a flat screwdriver, a quarter turn so the slot sits across the pipe. If there is none, turn off the stopcock. Leave the tap open to prove the water has stopped. The repair — a washer or a cartridge — can wait until the morning, or you can follow the leak repair guide.
- Some isolating valves have a small lever instead of a slot
- A tap stuck open is usually a failed cartridge or a spindle that has stripped
- Keep the rest of the house on water if the valve works
Mistake to avoid: Forcing the tap handle to shut it. The spindle strips completely and the tap then cannot be turned at all.
Get the heating back
15 minIf the boiler has stopped and its gauge reads low, let the system cool, then top it up through the filling link as the boiler's own instructions show, closing the link as soon as the needle sits in the green band. Then reset the boiler the way its instructions describe. If it shows a fault code that is not low pressure, or locks out again, stop.
- Read the gauge cold; a warm reading misleads
- Close the filling link fully afterwards
- Write down any fault code for the engineer
Mistake to avoid: Opening the boiler case to look for the fault. The inside of a gas boiler is restricted to Gas Safe registered engineers, and there is no small exception.
Call the right person with the right facts
10 minIf the problem is beyond the cards above, ring an emergency plumber and tell them exactly what happened, what you have turned off, and what you can see. For a leak in the street or outside your boundary, ring your water supplier. For sewage from a shared drain, ring the sewerage company. For gas, the gas emergency line.
- Ask for the call-out charge and the hourly rate before they set off
- Send photographs if they ask; it helps them bring the right parts
- Keep the stopcock off until they arrive
Mistake to avoid: Ringing a plumber without saying the water is already off. They may price it as a flooding emergency instead of a repair.
The mistakes that cost most
- Not knowing where the stopcock is until the ceiling is wet
- Turning the water off but not draining the pipes
- Going near wet electrics before switching off
- Flushing a blocked toilet again
- Opening the boiler to look for a fault
Stop here and get an emergency plumber
- Water will not stop with the stopcock off, or the stopcock is seized
- The leak is inside a wall, under a floor or above a ceiling
- Sewage is backing up into the house
- Anything involves gas, the inside of the boiler, or an unvented cylinder
| WHAT YOU SEE | WHY, AND THE FIX |
|---|---|
| Stopcock will not turn | It has seized. Do not force it with tools. Use the outside stopcock in the pavement chamber with a key, or ring your water supplier. |
| Water still coming with the stopcock off | The hot side is fed from a loft tank or a cylinder, not the mains. Close the tank's outlet valve and open the hot taps to drain it. |
| Toilet overflowing and plunger not working | The blockage may be past the toilet, in the drain outside. Lift the nearest inspection chamber cover; full means it is further down. |
| Boiler pressure at zero | The system has lost water. Top up through the filling link; if it falls again soon, there is a leak to find. |
| Cistern pouring into the overflow | The fill valve is not shutting off. Close the toilet's isolating valve now and replace or adjust the valve later. |
| Banging pipes after turning the water back on | Air in the pipes. Run each tap in turn until the flow is steady. |
| Water coming from the light fitting | Switch off at the board, keep away from the fitting, and catch the water. Have the circuit tested before switching back on. |
| Frozen pipe, no water from a tap | Turn the stopcock off, open the tap, and warm the pipe gently from the tap end back with a hairdryer or hot towels. Never use a flame. |
| Outside overflow pipe pouring water | A cistern or the loft tank's float valve is not shutting off. Find which tank or cistern feeds that overflow, close its isolating valve, and lower or replace the valve when the emergency is over. |
| Washing machine flooding the kitchen | Turn off its appliance valve behind the machine, or the stopcock, and unplug it once the floor round the socket is dry. A split fill hose is the usual culprit, and a new one comes from the machine's maker. |
WHAT YOU SAVE
What it costs to be ready
| Stopcock key | £10–£25 |
|---|---|
| Flange plunger | £4–£10 |
| Emergency pipe repair clamp | £16–£22 |
| Total, key only | £10–£25 |
| DIY total | £10–£25 |
Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.
An emergency plumber's guide price is for coming out at once. A key and a plunger bought in advance are the cheapest way to make the call shorter, or unnecessary.
RATHER NOT?
Emergency plumbers near you, with prices shown
The ones who cover your area, nearest first, with one score from every review. No account needed to look.
Or post the job free and let them come to you.
Open windows, lift wet rugs, and keep photographs and times for your insurer. Ask the insurer before throwing away damaged items.
Have an electrician test any circuit that got wet before relying on it.
Soaked carpet, underlay and plasterboard go to your council's household waste recycling centre, or a bulky waste collection for large items. Old pipe and fittings go to the metals container there. Find yours on the council website or the recycling pages for your nation.
A stopcock that would not turn, a valve that weeps, a missing key — sort them now, while the emergency is fresh.
Handling a plumbing emergency until help arrives: questions people ask
Turn off the water at the stopcock, then switch off the electricity if water is near it, then open the cold taps to drain the pipes. Most of the damage in a leak happens before the water is turned off.
Usually under the kitchen sink or where the supply pipe enters the house. There is often a second one outside in a small pavement chamber, turned with a long key.
Stop the cistern refilling by pushing the float down or closing its isolating valve, bail the pan to half full, and plunge with a flange plunger. Do not flush again.
On a sealed system, yes: top it up through the filling link with the system cold, close the link, and reset the boiler as its instructions show. If the pressure falls again soon, there is a leak.
Your water supplier. A leak on the public side of the supply, or water rising from the pavement, is theirs to deal with.
Locufy's UK price guide puts an emergency plumber at £80–£400 per job, typically £200 — the same three figures as the strip at the top of this page.
MORE GUIDES
More DIY guides
Sources — checked October 2026
- Worcester Bosch — system filling guide: the 1 to 1.5 bar band and the filling links
- Flowflex — compression fittings technical data and installation instructions
- HSE — electrical safety: frequently asked questions
- HSE — domestic gas safety: frequently asked questions (the gas emergency number)
- Water Supply (Water Fittings) Regulations 1999, regulation 5
- Water Supply (Water Fittings) (Scotland) Byelaws Extension Order 2024
- Water Supply (Water Fittings) Regulations (Northern Ireland) 2009
- gov.uk — Approved Document G: sanitation, hot water safety and water efficiency (England)
- Gas Safety (Installation and Use) Regulations 1998, regulation 3
- Gas Safety (Installation and Use) Regulations (Northern Ireland) 2004, regulation 3
- gov.uk — recycling collections: find your council (England and Wales)
- mygov.scot — find your council's recycling centre (Scotland)
- nidirect — recycling and reusing (Northern Ireland)
- B&Q — price check: stopcock keys
- B&Q — price check: plungers
- B&Q — price check: emergency pipe repair clamps