Right now

A leaking water heater. Power off, then water off.

A tank holds 40 to 50 gallons and the cold inlet keeps refilling it until you close the valve.

Turn off the heater before the water. Electric: switch off its breaker at the panel. Gas: turn the gas control to OFF. Then close the cold water valve on top of the tank. If you smell gas, leave the house and call the gas company from outside.

What is probably happening

Water at the base of the tank usually means the tank itself has rusted through. The manufacturer A.O. Smith says a cracked tank typically means a full replacement.
Water from the small pipe on the side or top is the temperature and pressure relief valve. It opens on high pressure or temperature and can be a valve or expansion problem, not a tank failure.
Water at the top fittings is often a loose or corroded connection, which is a repair.

Do this in the next five minutes

Kill power or gas to the heater first. Heating an empty or draining tank damages it and, on electric units, burns out the elements.
Close the cold water supply valve on the pipe going into the top of the tank.
If the leak is at the base, attach a garden hose to the drain valve at the bottom and run it to a floor drain or outside.
Mop or towel the floor and move stored items away from the tank.
Note the brand, model and the date on the label for the plumber.

Do not

Do not touch the breaker or the tank while standing in water. Kill the main from a dry spot or wait for help.
Do not try to patch a tank. A rusted tank is replaced, not sealed.
Do not plug the relief valve outlet to stop a drip. That valve is the safety device on a pressurized tank.

Who to call

A licensed plumber

The heater is the source and replacing it is licensed plumbing (and gas) work. Drying a small puddle on a concrete floor is usually not a restoration job.

Also: Water damage. If the heater sits over finished flooring or a closet and the floor has been wet for hours, call restoration for drying. Questions for that call ›

Get a free shortlist The seven questions for this trade

BestHonestPro is a free comparison resource, not a contractor. There is nothing to sign up for and we do not sell your details. When we begin connecting callers to contractors, we will be paid a referral fee by the contractor, never by you, and this line will say so.

What it should cost

$228 to $1,017 to repair, $850 to $1,800 to replace

Water heater repair, typical range, average $616. Full replacement range from the same source.

Source: Angi, water heater repair cost, updated August 2026. View source

National published range, not a quote for your job. The full cost table for this trade is on the plumbing page.

Ask this contractor, on the phone, before anyone comes out

Tap each one as you ask it.

Is the leak from the tank, the relief valve or a fitting, and how did you tell?
If it is a replacement, is the price for the same size and fuel, and does it include hauling the old one, a new relief valve and the permit?
Do I need an expansion tank, and is that in the quote?
Who pulls the permit, and will there be an inspection?

End the call if

A quote to replace the heater when the leak is a fitting or the relief valve, with no explanation.
No permit offered for a gas heater replacement.
Full payment up front, or cash only.

Insurance. Sudden and accidental water damage from a failed appliance is generally covered. The heater itself, when it fails from age, usually is not. Check the policy or call the agent (Texas Department of Insurance).

Where this comes from

Not my problem, tap through instead Every water damage answer