Water heater repair: what to know

What the job involves, what changes the price, and what to ask a pro.

What water heater repair is

Water heater repair diagnoses and fixes a unit that has no hot water, lukewarm water, leaks, noise, or a pilot or breaker that keeps tripping. A good repair finds the failed part and checks whether the tank itself is still sound.

Signs you need it

  • No hot water or lukewarm water, which can point to a failed element, a bad thermocouple or a dip tube that has broken
  • A pilot that will not stay lit or a gas burner that cuts out, which often means the thermocouple or gas control valve
  • A breaker that trips on an electric unit, which can point to a shorted heating element
  • Popping or rumbling from the tank, which means sediment has built up on the bottom
  • Water dripping from the T and P valve, the drain valve, or the bottom of the tank

What the pro does

  • Check the gas pressure, the pilot or ignition, the thermocouple or flame sensor, and the gas control valve on a gas unit
  • Test the upper and lower elements and their thermostats on an electric unit, using a meter for continuity and resistance
  • Inspect the anode rod, which protects the tank from corrosion, and replace it if it is wasted
  • Flush the tank to remove sediment, then check the drain valve and whether it seals
  • Check the T and P valve and replace it if it drips, sticks or fails the test
  • Look at the dip tube and the mixing valve if the water is lukewarm even with the heat working

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Fuel type and which part failed: a thermocouple is far simpler than a gas control valve or a burner
  • Whether the tank itself has failed, which means replacement, not repair
  • Age of the unit and whether parts are still available for it
  • Anode rod condition and whether the rod can be replaced in place
  • Access to the heater, including tight closets or crawl spaces
  • Whether the venting or gas supply needs to be checked after the part is changed

What a written quote should spell out

  • Diagnosis, with the part that failed and the test that showed it
  • Parts to be replaced, with the model match or part number
  • Whether the tank was flushed and the condition of the anode rod
  • Whether repair or replacement is recommended, and the reason
  • Any gas or electrical testing included in the visit

Questions to ask before you hire

  • What exactly failed, and how did you test it?
  • Is the tank leaking, or only a fitting or valve? A leaking tank is not repairable.
  • Can you check the anode rod and tell me how much life is left?
  • If the thermocouple or gas control valve failed, will you check the venting and draft too?
  • How old is the unit, and are parts still available for it?
  • Will you flush the tank, and what should the flush show about sediment?

Red flags

  • Pro who says the tank is shot without checking the parts, the anode rod or the valves
  • Pro who replaces a thermocouple or gas control valve without a gas pressure and draft check
  • Pro who bypasses or jumps a safety device, such as the high-limit switch or the T and P valve
  • Pro who will not show the test result for the element or the thermostat

What you can do yourself

A homeowner can check that the breaker is on, look for drips at the fittings, and read the owner's manual for what any status light means. Do not open the electrical access panel, or work on a gas burner, a gas control valve or a leaking tank yourself, since live wiring, gas faults and combustion problems can cause shock, carbon monoxide or fire.

Licenses and permits

Water heater repair is commonly done by licensed plumbers, and gas repair often requires a separate gas license or a licensed gas fitter. Electrical element work may need a licensed electrician in some areas, so check with your state or local licensing agency.

Water heater repair questions

Why does my water heater keep tripping the breaker?

On an electric unit, a heating element that is shorted to the tank or a failed thermostat usually causes it. A pro tests each element and thermostat to find which one has failed before any part is replaced.

Can a leaking water heater be repaired?

A leak from a fitting, the drain valve or the T and P valve can usually be repaired. A leak from the tank body means the tank has failed, and replacement is the repair.

How often should the tank be flushed?

Sediment buildup depends on the water supply and the tank design. Ask the pro to check the sediment when they inspect the tank, and to set a schedule based on what they find.

Why does my hot water smell like rotten eggs?

Certain bacteria in the tank can react with a magnesium or aluminum anode rod and create that smell. The pro can check the anode rod type and the tank, and recommend a fix based on the source.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

Edit history

How it works

  1. 1. Describe the job

    Pick the service, add your ZIP and a sentence about what is going on.

  2. 2. Pick the pros you want

    See pros who serve your ZIP and choose who you want to hear from.

  3. 3. They reach out

    They contact you the way you chose: phone, email or in-app messages.

More plumbing guides

Find a pro near you

Find a pro

About this guide

Request water heater repair