What should I do right now if my water heater is leaking?
Act in this order. Most leaks are slow enough to handle safely, but hot water, gas and electricity all need respect.
- If you smell gas, stop. Leave the home and call 911, then PG&E at 1-800-743-5000. PG&E says not to use light switches, matches or flashlights to look for a leak.
- Turn off the heat: switch off the breaker for an electric water heater, or turn a gas heater's control knob to off.
- Close the cold-water supply valve on the pipe feeding the top of the tank. If it won't close, shut the home's main water valve.
- Stay clear of the relief valve and its pipe. CPSC says 140°F water causes third-degree burns in 6 seconds.
- Move belongings, dry the area and take photos for your records.
- Call (916) 712-7030 to be connected with a local plumber, and do not drain a hot tank until it has cooled.
Why is my water heater leaking?
Start at the top and work down. Water at the top usually comes from the inlet or outlet connections or the supply connectors. Water from the relief valve or its drain pipe means the valve is opening, from high temperature or pressure, sediment in the valve or a failing valve, according to HomeGuide. A drip at the drain valve near the bottom is common on older tanks; Fixr notes drain valves can wear out and start leaking right after the tank is drained.
Water coming from under the tank, with dry fittings above, usually means the tank itself has corroded through. The anode rod inside a tank is there to absorb corrosion, and HomeGuide says plumbers recommend replacing it every 3 to 5 years. Once the steel tank leaks, it cannot be patched. With heat pump water heaters, also check the condensate line, which DOE guidance says must carry away water the unit produces in normal operation.
Is my water heater's relief valve supposed to drip?
No. The temperature and pressure relief valve is a safety device that releases water when the tank gets too hot or pressure gets too high. A drip is a warning to find the cause, not a part to plug. California's plumbing code requires the valve's drain to run to the outside of the building and to be no smaller than the valve outlet.
A common cause is thermal expansion. When water heats up it expands, and if a check valve or backflow preventer keeps that pressure from flowing back to the main, the code requires a listed thermal expansion tank or similar device. Roseville's building division says the plumbing code calls for one on water heating systems to relieve excess pressure during heating.
Can a leaking water heater be repaired?
Often, if the leak is not the tank. Fixr puts valve repairs at $75 to $150, relief valve replacement at $100 to $250 and drain valve replacement at $100 to $200 nationally; HomeGuide lists relief valve replacement at $50 to $300. Loose or worn supply connectors are usually a quick fix. If the tank body leaks, HomeGuide says replacement typically runs $600 to $1,800. A replacement in Sacramento needs a permit and must meet current strapping and expansion-tank rules.
Is a leaking water heater dangerous?
The water damage is the most common harm, but not the only one. Water near an electric heater's wiring is a shock risk, so shut the breaker before touching anything. A leak can also be a sign of high pressure that strains the relief valve. If a gas water heater's vent is knocked loose while you deal with the leak, combustion gases can back-draft; the EPA lists back-drafting gas water heaters as a carbon monoxide source.
Location matters too. Where a water heater sits in an attic or over a ceiling or floor that a leak would damage, the plumbing code calls for a watertight drain pan at least 1.5 inches deep with a 3/4-inch drain. And because California requires straps on every residential water heater, a tank that has been loosened while you work on a leak should be re-secured.
| Where the water is | Likely cause | Typical fix |
|---|---|---|
| Top of tank, at pipe connections | Loose fitting or worn supply connector | Tighten or replace the connector |
| Relief valve or its drain pipe | High temperature or pressure, thermal expansion, sediment or a failing valve | Check pressure and expansion tank; replace the valve ($50–$300) |
| Drain valve near the bottom | Worn or loose drain valve, often after draining | Replace the drain valve ($100–$200) |
| Under the tank with dry fittings above | Corroded tank | Replace the water heater ($600–$1,800 per HomeGuide) |
| Near a heat pump water heater | Condensate line clogged or disconnected | Clear or reconnect the condensate drain |
| Puddle with no visible drip | Nearby pipes, a softener or another appliance | Dry the floor and trace the source |
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Frequently asked questions
Why is water leaking from the bottom of my water heater?
Should I turn off my water heater if it is leaking?
Is a dripping relief valve an emergency?
Sources
- How much does water heater repair cost? (2025–2026) — HomeGuide
- Water Heater Repair Cost (updated Aug. 29, 2025) — Fixr
- Gas safety — PG&E
- Avoiding Tap Water Scalds (Document 5098) — U.S. Consumer Product Safety Commission
- New and Replacement Water Heater Installations: Selected excerpts from the California Plumbing Code — San Bernardino County Land Use Services, Building and Safety Division
- Water Heater Installations (California Plumbing Code excerpts, incl. CPC 507.5 drainage pan) — City of Yorba Linda Building & Safety
- Thermal Expansion Tank Requirements for Water Heaters — City of Roseville Development Services, Building Division
- Decision Guidance for Heat Pump Water Heaters, Level 3 (sizing worksheet, recovery, condensate) — U.S. Department of Energy, Building Science Education Solution Center
- Carbon Monoxide's Impact on Indoor Air Quality — U.S. Environmental Protection Agency
- Health and Safety Code section 19211 (water heater seismic bracing) — State of California, via california.public.law
- Water Heater (Residential or Commercial): Fees by Project — City of Sacramento Community Development
- Water heater repair services: costs and FAQs (Los Angeles page, 2026) — HomeGuide