Water heater leaking: what to do right now

Safety first: gas, electricity and scalding water

A leaking water heater brings three hazards together: water, electricity or gas, and water hot enough to burn. Deal with them before you think about the cause. The U.S. Consumer Product Safety Commission notes that most adults suffer third-degree burns after two seconds in 150°F water, so do not put your hands under a leak or open a valve near a hot tank without gloves.

1. If you smell gas (a rotten-egg or sulfur odor) or hear hissing near a gas water heater, do not touch switches or controls. Leave the home, then call 911 and Columbia Gas of Ohio at 1-800-344-4077 from a safe place outside, as the utility instructs.
2. If water has reached outlets, cords, the electrical panel or the furnace, stay out of it. Shut off power only from a dry spot.
3. Keep children and pets away from the tank, the drain pan and any hot water on the floor.
4. If a carbon monoxide alarm sounds, get everyone outside and call 911.

Shut it down in four steps

When it is safe to reach the heater, these steps stop new water from entering the tank and keep the heater from firing while it may be empty or damaged.

1. Close the cold-water supply valve. It is on the pipe that feeds the top of the tank, usually marked cold or blue. Turn a wheel handle clockwise until it stops, or turn a lever a quarter turn so it sits across the pipe. If that valve will not close or there is none, close the home's main water shutoff; in many Columbus-area homes it is in the basement near the front foundation wall.
2. Turn the heater off. For an electric heater, switch off its breaker at the panel. For a gas heater, turn the gas control knob to Off or Pilot. Do not relight the pilot or adjust the gas line yourself if you are unsure.
3. Contain the water. Move stored boxes, push a towel dam around the base and use a wet vacuum on a dry, safe circuit if you have one.
4. Take photos of the label, the leak and any damage. The label shows the brand, model, serial number and often the manufacture date, which a plumber and your insurer will both ask for.

Find where the water is coming from

Once the heater is off, dry the area and watch for where new water appears. Where it comes from decides whether you are looking at a repair or a replacement.

1. Top of the tank: the hot and cold pipe connections, a flexible supply line or the shutoff valve may be leaking. These are usually repairable.
2. The temperature and pressure (T&P) relief valve on the side or top, or its discharge pipe running down the side: see the next section.
3. The drain valve near the bottom: it may be slightly open, or its washer or threads may be leaking.
4. Under the tank or through rust on the tank body: a corroded tank cannot be patched and will need replacing.
5. An access panel on an electric heater: water there can point to a leaking heating element gasket. Leave panels closed and let a technician open them.

Water from the relief valve: do not plug it

The T&P relief valve is a safety device that opens to release water if temperature or pressure in the tank gets too high. Watts, a relief-valve manufacturer, says that in normal operation no water should come out of it. A small drip after the heater runs can point to high household water pressure or thermal expansion, which a plumber may address with a pressure-reducing valve or an expansion tank. A large flow of hot water from the discharge pipe can mean an unsafe condition, so turn the heater off and have it checked. Never cap, plug or remove the discharge pipe to stop the water.

Is it really a leak? Condensation in cold weather

Late fall and winter bring a common false alarm in Central Ohio. When very cold water refills a gas water heater after heavy use, moisture from the burner's exhaust can condense on the cool tank and drip onto the burner or the floor, sometimes with a sizzling sound. Manufacturers such as A. O. Smith say this condensation usually clears once the water warms, which can take one to two hours. If the floor is still getting wet after the tank is fully hot, or the water is rusty, treat it as a real leak. Water at the draft hood on top of a gas heater is different: the manufacturer manuals point to a venting problem, which needs a technician.

Repair or replace?

A leak from a fitting, supply line, drain valve or relief valve is often a parts repair. A leak from the tank body, or a tank with heavy rust at the base, usually means replacement, because the steel tank cannot be sealed from the outside. Age, repair history and warranty also matter; our water heater repair-or-replace page walks through those factors. Ask any provider to show you where the leak is before you agree to a replacement.

• Water heater: repair or replace?
• Columbus water heater help

Permits for a replacement in Columbus

In the City of Columbus, replacing a hot water tank requires a permit but not plan review, according to the city's Building and Zoning Services guide to typical residential projects. City code says a plumbing permit may be obtained by a licensed plumbing contractor registered with the city, or by an occupying homeowner doing the work, and it exempts simple repairs such as mending a leaking valve or water heater. Suburbs such as Dublin, Westerville, Hilliard, Grove City, Gahanna, Reynoldsburg, Upper Arlington and Worthington have their own building departments, so confirm the rules with your city. Ask the provider who pulls the permit and schedules the inspection.

• Dublin
• Westerville
• Hilliard
• Grove City
• Gahanna
• Reynoldsburg
• Upper Arlington
• Worthington

When to call a plumber

Call a plumber when water is coming from the tank body, when the cold-water valve will not close, when the relief valve keeps discharging, when you see water at the burner or draft hood that is not simple condensation, or when you have no hot water and the heater is gas and you are not comfortable working near its controls. Have the label photo, the location of the leak and how long it has been happening ready, and ask about pricing and timing on the call. If water has spread to other rooms, see our emergency plumbing page too.

• Columbus water heater help
• Columbus emergency plumbing
• All Columbus home-service guides

Talk to a local provider

If your water heater is leaking from the tank, the relief valve keeps releasing water, or you cannot stop the leak, call the number on this page to ask about a possible referral to an independent local provider serving Columbus and nearby suburbs such as Dublin, Westerville, Hilliard, Grove City, Gahanna, Reynoldsburg, Upper Arlington and Worthington. Ohio Service Hub is a referral service, not a contractor. Availability, pricing and arrival times are set by the provider you speak with, so confirm them on the call. Calls may be recorded. Independent provider routing is not yet verified for this general inquiry number.

Common homeowner questions

Government and primary-source references

• Columbia Gas of Ohio — How to recognize a gas leak
• U.S. CPSC — Avoiding Tap Water Scalds
• Watts — T&P relief valves
• A. O. Smith — Why is my water heater leaking?
• City of Columbus — Typical Residential Projects (permits)
• Columbus City Code § 4113.61 — Plumbing permit

External references support general guidance. They do not verify any specific contractor or provide a booking.