A leaking water heater is usually caused by a loose fitting, a bad valve, too much pressure, condensation, or a tank that has corroded and failed. If water is pooling under the tank and you can’t find an obvious external source, the tank itself may be leaking and the unit may need replacement.

Common leak sources

  • Loose inlet or outlet connections. Water can seep from the cold-water inlet or hot-water outlet if fittings loosen over time.
  • Drain valve problem. The drain valve at the bottom of the tank can drip if it is loose or damaged.
  • Temperature and pressure relief valve. If this valve is leaking, the tank may be running too hot or building too much pressure.
  • Condensation. Small amounts of water around the tank can be condensation, especially in colder months.
  • Corroded tank. If the inside of the tank has rusted through, that is usually not a repairable leak.

What to do now

  1. Turn off power to the heater.
  2. Shut off the cold-water supply.
  3. Wipe up the water and check where it reappears.
  4. Look at the top connections, drain valve, and pressure relief valve.
  5. Call a plumber if the leak is steady or coming from the tank body itself.

When it is urgent

  • Water is actively spraying or pooling fast.
  • The relief valve is discharging continuously.
  • You smell gas near a gas heater.
  • The tank shell is rusted or leaking from the bottom.

Practical takeaway

If the leak is from a fitting or valve, it may be fixable. If the leak is from the tank itself, replacement is usually the real answer.