A leaking valve or fitting. Usually a repair, not a new heater.
A drip from a fitting is slow, but the relief valve dripping can mean pressure or temperature is too high, which is a safety issue worth a same-day look.
What is probably happening
- A drip from the pipe on the side is the temperature and pressure relief valve doing its job, or a worn valve. Either way, a plumber should check the pressure.
- A drip at the bottom drain tap is a worn tap, a cheap part.
- A drip at the top is a loose or corroded inlet or outlet fitting.
Do this in the next five minutes
- Dry the area and watch for ten minutes to see exactly where the water starts.
- If it is the relief valve pipe, note whether it drips only when the heater is heating. Tell the plumber.
- Put a container under the drip.
- If the drip is steady or growing, close the cold inlet valve and turn the heater off until the plumber arrives.
Do not
- Do not cap or plug the relief valve pipe. It is the tank's safety vent.
- Do not tighten a fitting hard on an old heater. Corroded fittings snap.
- Do not agree to a whole new heater for a $200 valve unless the tank is near the end of its 10 to 15 year life anyway.
Who to call
A licensed plumber
Relief valves, drain taps and fittings are standard plumbing parts, and a plumber can also test house pressure while there.
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What it should cost
$228 to $1,017, averaging $616
Water heater repair, national range. Relief valve replacement up to $200
Source: Angi, water heater repair cost, updated August 2026. View source
National published range, not a quote for your job. The full cost table for this trade is on the plumbing page.
Ask this contractor, on the phone, before anyone comes out
Tap each one as you ask it.
- Will you measure the house water pressure and tell me the number?
- If it is the relief valve, do I also need an expansion tank, and why?
- What is the age of my heater from the serial number, and would you repair it at that age?
- Is the service call fee applied to the repair if I go ahead?
End the call if
- A push to replace the heater before the drip source is even identified.
- A plumber who plugs the relief valve outlet instead of replacing the valve.
- A quote that does not name the part.