A leaking water heater is stressful, but most leaks start slowly. The first few minutes are about stopping the water and making it safe.
Do this first
- Shut off the cold water to the heater. It's the valve on the cold-water pipe going into the top of the heater. Turn a round handle clockwise until it stops, or turn a lever a quarter turn so it's crosswise to the pipe. If you can't find it or it won't close, shut off the main water valve.
- Turn off the energy. Electric: switch off the water heater's breaker at the panel. Gas: turn the control knob on the front of the heater to Off. If water has reached outlets or wiring, don't stand in it; shut off power at the panel only if you can do it from a dry spot.
- Contain the water. Towels, a wet-dry vacuum, and move anything on the floor nearby.
- Take photos of the heater, the label, and any damage. They help with the repair and with insurance.
Find where the water is coming from
- Pipe connections on top: a loose fitting, a corroded nipple, or a worn flexible connector. Usually repairable.
- The relief valve or its discharge pipe: the temperature and pressure relief valve is the brass valve on the side or top with a pipe running down the side of the tank. If it's dripping or discharging, the pressure or temperature is too high, or the valve is wearing out. A common cause is thermal expansion in a house with a pressure-reducing valve or check valve (when you need an expansion tank). Never cap or plug that pipe.
- The drain valve near the bottom: a slow drip from the drain valve can be fixed by replacing the valve.
- The tank itself: if the top and the drain valve are dry but water keeps pooling underneath, the steel tank has usually corroded through. That can't be repaired.
- Condensation: a gas heater filled with very cold water, common in a Colorado winter, can drip condensation. It stops once the tank heats up.
- Something else nearby: a furnace or air conditioner condensate line, a water softener, or a pipe overhead can drip onto the heater and look like a leak.
Repair or replace?
Leaks at fittings, connectors, the drain valve, or the relief valve can usually be repaired, especially on a heater under about eight years old. A leak from the tank itself means replacement, and so does a heater about ten years or older that's starting to leak. Most replacements are done the same day they're quoted, with the old unit hauled away. Water heater repair and replacement →
Is it an emergency?
A drip from a fitting isn't, as long as the water is off. A tank that's actively leaking from the bottom can fail all at once and release everything in it, often 40 or 50 gallons, so shut off the cold water right away. If water is spreading toward a finished floor or the unit below, call or text (720) 818-5569; active leaks get same-day service.
Prevent the next one
- Put the heater in a drain pan piped to a floor drain, especially over a finished floor or in a closet
- Flush the tank once a year; Front Range hard water builds sediment that wears the tank (how hard is your water?)
- Check the anode rod every few years and replace it before it's used up
- Replace the heater on your schedule once it's past about 10 years (how long they last)