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Water Heater Leaking From The Top

Three common causes, what is safe to check yourself, and when to call a pro.

The temperature and pressure relief valve is discharging

Pro required

Most common

Safe to check yourself

  • Look at the discharge pipe running from that valve to the floor or outside for wetness or dripping
  • Check the thermostat setting to see if it looks unusually high

The T&P valve is a safety device that releases pressure so the tank doesn't rupture. If it's discharging, that signals a real pressure or temperature problem, and it needs a licensed technician to diagnose.

Loose or corroded inlet or outlet pipe fittings

Pro required

Common

Safe to check yourself

  • Look at the pipe connections on top of the tank for greenish corrosion or mineral buildup
  • Feel around each fitting for dampness

Fittings on top of a water heater sit close to hot water lines and, on gas or electric units, close to those connections too. Tightening or replacing them safely is a plumber's job.

The safety valve itself is old and reaching the end of its life

Pro required

Less common

Safe to check yourself

  • Check how old the water heater is, since these valves are typically replaced periodically
  • Look at whether the leak is a slow weep versus a steady stream

Replacing a safety valve correctly, and confirming pressure and temperature are in normal range first, needs a licensed technician.

DIY or pro, at a glance

  • The temperature and pressure relief valve is dischargingPro required
  • Loose or corroded inlet or outlet pipe fittingsPro required
  • The safety valve itself is old and reaching the end of its lifePro required

When more than one cause is possible, start from the most common one above. If you are not sure which cause applies, this one is a pro job.

Not sure if it is worth fixing?

Run the numbers on repair versus replacement cost for your water heater.

See repair or replace costs for a water heater

Last updated 2026-07-03.