Water Heater Leaking? Do This Right Away

A leaking water heater rarely fixes itself. Once a tank starts to weep, corrosion is usually the cause, and it only gets worse — sometimes ending in a full rupture that dumps 40 to 80 gallons across your floor. The move is to stop the water and power now, contain the leak, and figure out whether you're repairing or replacing.

Work the steps in order. If it's a gas unit, note the gas caution below.

Do these things right now

1. Shut off the water. Close the cold-water shutoff valve on top of the heater (turn it clockwise). If it won't budge or there isn't one, shut off the home's main water supply.

2. Shut off the power or gas.

• Electric: Turn off the water heater's breaker at the electrical panel. Never work around a leaking electric heater with the power on.
• Gas: Turn the gas control valve to "OFF" (or "Pilot"). Do not turn off the shutoff if you smell gas — instead, leave and call your utility. If you smell rotten eggs or sulfur, get out and call 911 or your gas company from outside.

3. Find where it's leaking. Check the cold and hot connections up top, the temperature-and-pressure (T&P) relief valve and its discharge tube, the drain valve at the bottom, and the tank body itself. A dripping connection or valve may be fixable. Water seeping from the tank body means the tank is done.

4. Contain and document. Mop and towel the water, move anything valuable off the floor, and drop towels or a pan under the drip. Photograph the leak and any water damage for insurance before you clean up.

5. Drain it if it's leaking badly, then call a pro. For a significant leak, attach a hose to the drain valve and run it to a floor drain or outside to empty the tank and stop the flood. Then call a plumber. A slow drip you've contained can often wait until morning to avoid an after-hours rate.

Where the leak is coming from — and what it means

Not every "leaking water heater" needs a new tank. Trace the water to its source:

• Cold or hot connection at the top. A loose or corroded fitting. Often tightened or replaced — a repair.
• T&P (temperature-and-pressure) relief valve. If it's discharging, the tank may be overpressured (a real safety issue) or the valve is worn. Never plug it; get it checked.
• Drain valve at the bottom. Can be replaced fairly easily if it's dripping.
• The tank body itself. Water weeping from the bottom or side of the tank means internal corrosion has breached the steel. There's no repair — the tank must be replaced.
• Condensation, not a leak. On humid days or with a brand-new tank, droplets can be harmless condensation. Dry it, watch it, and confirm before assuming the worst.

A rule of thumb: leaks at valves and fittings are often fixable; leaks from the tank shell mean replacement.

When to DIY vs. call a pro

You can safely shut everything off, contain the water, and drain the tank. A confident DIYer can also replace a leaking drain valve or T&P valve, or tighten a loose connection.

Call a plumber when:

• Water is seeping from the tank body itself (replacement).
• The T&P valve is discharging repeatedly — that can signal dangerous overpressure.
• It's a gas unit and you're unsure about the gas connection or venting.
• The unit is 10+ years old and leaking (usually not worth repairing).
• You'd rather not wrestle a 150-pound tank.

Never cap or plug a discharging T&P valve — it's a safety device that prevents the tank from becoming a pressure hazard.

What it costs

| Job | Typical 2026 range | |---|---| | After-hours plumber call-out | $150–$500 | | T&P valve / drain valve replacement | $150–$400 | | Tank water heater replacement | $880–$1,825 | | Tankless water heater (installed) | $1,400–$5,500 | | Water damage restoration (if it flooded) | $1,384–$6,384 |

A tank leaking from the body means replacement — see the water heater replacement cost guide. If it flooded the room, the water damage restoration cost guide covers drying. You can also estimate your local cost.

Repair or replace? The quick math

Once the tank is empty and safe, decide before you spend:

• Under ~6 years old, leak at a valve or fitting: repair. You'll get years more out of it.
• 8–12 years old, leaking from the tank body: replace. Tanks last 8–12 years, and a corroded shell only gets worse — often failing completely soon after.
• A repair quote topping half the price of a new unit: replace.
• Repeated problems (sediment, rust in the hot water, rumbling): replace and start fresh.

If you're replacing, consider whether a tankless unit fits your household — it costs more upfront but lasts longer. Weigh it against a standard tank in the water heater replacement cost guide.

Insurance note

A sudden tank rupture that floods a room is often covered as sudden, accidental water damage; a slow leak you ignored for months usually isn't. Photograph the leak and any damage before cleanup, keep receipts, and file promptly. The water damage restoration cost guide covers what drying and rebuild run if it flooded.

Prevent the next leak

• Flush the tank once a year to clear sediment that accelerates corrosion.
• Check the anode rod every few years and replace it when it's spent — it's what protects the tank.
• Test the T&P valve annually.
• Install a drip pan with a drain line under the tank.
• Add a leak sensor or auto-shutoff at the base — cheap insurance against a rupture.
• Replace tanks proactively at 10–12 years; that's about their lifespan.

Our water heater maintenance guide has the full routine, and what to do about a burst pipe covers the wider flooding scenario.

FAQ

Is a leaking water heater an emergency? A slow drip you've contained can wait. A tank spraying or rupturing is an emergency — shut off the water and power and drain it.

Can a leaking water heater be repaired? If the leak is at a valve or connection, yes. If it's leaking from the tank body, no — the tank is corroded through and needs replacing.

Why is my T&P valve leaking? It may be doing its job (relieving overpressure) or it may be worn. Repeated discharge can signal a thermostat or pressure problem — don't cap it; call a plumber.

Should I repair or replace? If the unit is under ~8 years old and the leak is a valve, repair. If it's 10+ years old or leaking from the tank, replace. See the replacement cost guide.

How long do water heaters last? Tank units typically last 8–12 years. Past that, a leak usually means it's time to replace.

Water is pooling but I can't tell where it's from — what do I do? Dry the whole area, then watch. Check the connections up top, the T&P valve and its tube, the drain valve, and the tank base. If water returns at the tank body, it's a replacement; at a valve or fitting, it may be a repair.

Can a small water heater leak wait? A tiny, contained drip can often wait until morning to avoid an after-hours rate — but shut off the water supply to the unit and keep an eye on it. Corrosion leaks only grow.

Is it dangerous to have a leaking gas water heater? The leak itself is a water problem, but if you smell gas, that's a separate emergency — leave and call your utility. Also keep the burner area dry and don't let water reach the gas controls.

Cost figures are 2026 national averages for general information only, not quotes. Your price depends on your specific job, home, and location. Always get a written estimate before authorizing work. On a gas unit, if you smell gas (a rotten-egg odor), leave the home and call 911 or your gas utility from outside — do not operate any switches or valves.