Water heater failed? Stop the water first

What is emergency water heater replacement?

If a water heater is discharging water into your home, the priority is stopping the flow, not choosing an appliance. Close the cold water supply valve at the top of the tank - or the main shut-off if that valve will not move - then kill the fuel or power, gas at the valve or electric at the breaker, so the unit is not heating an emptying tank. Then, and only then, work out whether this is genuinely a tonight job. A contained leak with the water off usually is not, and one business day of patience typically buys you a better unit at a lower price.

Signs you need emergency water heater replacement

• Water is running or spraying from the tank rather than dripping, and it is not slowing
• The tank has failed above a finished ceiling, in an attic, or anywhere the water is reaching another room
• The pan under the unit is overflowing, or there is no pan at all
• The relief valve is discharging continuously and the discharge line is hot
• You can hear the burner or elements running while water is visibly escaping
• The unit is in a garage or basement near stored belongings, an electrical panel, or a furnace
• You have no hot water in freezing weather and there are vulnerable people in the house

Seeing something not on this list? Browse water heater problems by symptom →

How emergency water heater replacement actually works

1. 1

   Close the cold supply, then cut the fuel or power

   The cold inlet valve sits at the top of the tank on the cold side; closing it stops the tank refilling as it empties. If it is seized - and decade-old valves often are - go to the main shut-off for the house instead. Next, turn a gas unit's control to its off position and close the gas valve at the appliance; on an electric unit, switch the breaker off. An unattended unit heating a draining tank is the situation you are trying to end.

   Watch forForcing a seized valve hard enough to snap it. If it will not turn with reasonable effort, leave it and use the main. A broken inlet valve turns a manageable leak into an uncontrolled one.

2. 2

   Limit the damage while you wait

   Open a hot tap somewhere in the house to relieve pressure and let the tank drain down through it rather than through the failure. Move anything absorbent or valuable out of the water's path, get air moving over the wet area, and photograph everything before you clean up - wet cardboard and soaked drywall are much easier to claim for with pictures taken at the time.

   Watch forDraining a tank onto a finished floor with a garden hose that then siphons back. Route the hose to a drain or outside and confirm it is actually running downhill the whole way.

3. 3

   Decide honestly whether this is a tonight job

   With the water off and the fuel isolated, an inert tank in a basement is no longer an emergency - it is an inconvenience. The genuine after-hours cases are water you cannot stop, active damage to finished space, and a gas smell. Everything else is a cold shower and a phone call in the morning.

   Watch forBeing told that everything must happen tonight by the only company answering the phone at 11pm. That is the moment with the least competition and the least leverage you will ever have on this purchase.

4. 4

   If it is genuinely tonight, control what you can

   Ask what unit is coming and what its capacity is before it arrives. Ask what the after-hours rate is and when it starts. Ask whether the permit is being pulled and when the inspection will happen - emergency work still gets inspected, and a permit skipped in a crisis is still an open problem at resale.

   Watch forAccepting whatever is on the truck. Emergency stock is whatever the company buys in volume, not what suits your house, and it can quietly lock you out of a type change you had been considering for years.

5. 5

   If it can wait, use the day properly

   A single business day gets you two or three quotes, standard-rate labour, the unit you actually chose, and the option of a different type entirely. That is a large amount of value bought with one uncomfortable morning. Meanwhile the unit stays isolated and the house stays dry.

   Watch forWaiting without isolating. "It has mostly stopped" is not a plan - leave the supply closed and the power off until somebody has looked at it, however inconvenient that is.

What does emergency water heater replacement cost?

After-hours and same-day replacements typically carry a premium over standard-rate work, often adding a few hundred dollars in labour on top of a normal installed price. Where the leak is contained and the water is off, waiting one business day usually removes that premium entirely. See the cost guide.

See the full emergency water heater replacement cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →