If your water heater is leaking, shut off the cold water supply to the heater, then turn off the power at the breaker for an electric unit or set a gas unit to off, and call a plumber. A small drip at a fitting is a repair. Water coming from the tank body means the tank has corroded through and the heater needs replacing. Do not cap or plug the relief valve. This page explains each kind of leak and how the call works in Los Angeles, and the wider range of jobs is on our water heater repair and replacement page.
What should you do first when a water heater is leaking?
Based on what most plumbers advise, close the cold water valve on top of the heater, then switch off the breaker for an electric unit, or turn a gas unit's control to off and close the gas valve a quarter turn. If the valve is stuck, close the main water shut-off. Keep clear of hot water. If you smell gas, leave the building and call SoCalGas from outside.
The order is water first, then power or gas. If the leak is near electric wiring, switch off the breaker before you step into standing water, and do not touch anything electrical while wet. The SoCalGas emergency line is 1-800-427-2200, and you call 911 if there is immediate danger. Open a hot tap somewhere in the house to ease pressure if the leak is heavy, and mop up water so it does not reach walls or flooring. A hot water leak in a closet or a garage can spread quickly.
Never touch the relief valve discharge pipe while hot water is flowing from it. The water can scald.
Where is the leak coming from, and what does it mean?
The location tells you most of what you need. Water from the top fittings, the drain valve or the heating element gasket is usually repairable. Water pooling from the bottom or seeping through the tank jacket means the tank has failed. Water from the relief valve pipe points to a pressure or temperature problem, not a failed valve every time.
| Where the water is | Most likely cause | Usual outcome |
|---|---|---|
| Top: inlet or outlet fittings, shut-off valve | Loose or corroded connection | Repair |
| Side: drain valve, element or access panel gasket | Worn valve or gasket | Repair |
| Pipe from the relief valve | Pressure or temperature too high, or a failing valve | Repair, after checking pressure |
| Bottom or around the base, tank wet to the touch | Tank corroded through | Replacement |
| Puddle only while a gas unit heats cold water | Condensation | Often normal, watch it |
A leak from the body of the tank cannot be patched. Tanks corrode from the inside, so by the time water shows outside, the damage is done. If you are unsure, dry the heater with a towel and look for the first place that gets wet again. Our guide to repairing water heater leakage walks through finding the source in more detail.
Is a leaking water heater an emergency?
Treat it as an emergency if water is spreading, comes from the tank body, or is near electrical parts or a gas burner. Water reaching a gas unit's burner or control is a hazard, and an electric unit leaking near wiring is a shock risk. A slow drip at a fitting can wait for the next available visit, as long as the water is off.
Once you have shut off the supply, the urgency falls, because no more water is coming in. You still want it seen within a day or two, because standing water ruins drywall and flooring quickly, and because a heater left with its supply off means no hot water. If it is after hours and the leak is heavy, see our emergency water heater repair page. We can arrange a local plumber to come to you.
Can a leaking water heater be repaired, or does it need replacing?
A leak from a fitting, valve or gasket can usually be repaired, because those parts come apart and are cheap compared with the tank. A leak from the tank itself cannot be repaired, and the heater has to be replaced. On an old tank, a plumber may also advise replacement even when the leak is small.
Age matters, and so do the temperatures the heater has run at for years. Tanks wear out from the inside, and a heater that has outlived its expected life with several faults is a poor candidate for repair. Our water heater replacement cost page gives the price ranges. If the heater is young and the leak is at a fitting, the repair is small. If the tank is the problem, you will want to look at replacement, and at whether a tankless water heater suits your home better than another tank.
Why does the relief valve drip, and is that a leak?
A dripping relief valve is a warning. Either the valve has worn and is leaking, or water pressure or temperature in the tank is too high. Pressure rising when water heats in a closed system is common, and an expansion tank can cure it. Never cap the valve or its pipe.
The temperature and pressure relief valve is a safety device. It opens to release pressure before the tank is at risk. If it drips once after testing, that is usual, but if it drips steadily, have the water pressure checked and ask the plumber about an expansion tank before you swap the valve. Our pages on relief valve replacement and expansion tanks cover each in turn.
What causes water heaters to leak in Los Angeles homes?
Age, sediment and corrosion are the usual causes, and hard water speeds up scale. LADWP classes water above 7 grains per gallon as hard, and 2022 averages ran from 8.6 grains in the Valley and West Los Angeles to 16.3 in the east and the harbor area. Scale and sediment build up in the tank, and an anode rod that is used up lets the tank corrode.
An anode rod protects the steel tank by corroding in its place. When it is gone, the tank starts to go instead, which is why our page on anode rod replacement matters for the heater's life. Movement is another cause in earthquake country. California law requires water heaters to be braced or strapped against earthquake motion, and a heater that is loose can strain its pipes and fittings. A plumber replacing a heater has to restrap it, and the city inspector checks it.
What does a plumber do on a water heater leak visit?
The plumber finds the source, shuts off and drains the heater if needed, and tells you whether it is a repair or a replacement. For a repair they replace the fitting, valve or gasket, refill, purge air, and check for leaks. For a replacement they remove the old tank and install the new one, which needs a permit in the City of Los Angeles.
LADBS requires a plumbing permit to replace a gas water heater in a single-family home, with a narrow exception for like-for-like replacement by a registered contractor. Plumbers normally handle the permit and bracing so you do not have to. If you would like us to arrange a visit, tell us what you have found on the quote page, and a written quote comes before any work starts. The home page lists the other jobs we arrange.
Common questions
How much does it cost to fix a leaking water heater?
It depends on the leak. A fitting, valve or gasket repair is a modest job. A tank replacement costs much more, and published guides put a new installed tank at roughly $1,300 to $2,400. Treat that as a guide only. A written quote from the plumber shows parts, labor and any permit before work starts.
Can I use my water heater while it is leaking?
No. Shut it off. An electric unit running with a leak near the wiring is a shock risk, and a gas unit with water near the burner is a hazard. An electric tank should never be powered while it may be empty. Leave it off until a plumber has seen it.
Will my water heater leak get worse?
Usually yes. A slow drip at a fitting can be stopped by a plumber for little cost, but a leak from the tank body only grows as the steel rusts through, sometimes into a full release of the tank's water. Shut the supply off, put a bucket or towels down, and arrange a visit.
Should I drain the water heater myself?
You can drain a tank through the drain valve at the bottom with a hose, but the water is hot and the tank holds around 40 to 50 gallons in a typical home. Turn the power or gas off first, wait for the water to cool, and open a hot tap to let air in. If unsure, let the plumber do it.
Does homeowners insurance cover a water heater leak?
That depends entirely on your policy and on how the damage happened, so check with your insurer and keep photos. Some policies cover sudden water damage, but not the cost of the heater itself or slow leaks left unattended. Do not delay shutting off the water, since insurers expect you to limit the damage.