Plumbing Emergency Avg. cost: $900
Water Heater Leaking: Causes, Fixes & When to Call a Plumber
If your water heater is leaking from the tank body, it needs to be replaced — tank corrosion is irreversible. Leaks from fittings, connections, or the pressure relief valve may be repairable. Turn off power (or gas) to the unit and the cold water supply while you determine the source.
Find an Emergency Plumber NowWhat Causes Water Heater Leaking?
- Tank corrosion from sediment buildup (older units)
- Faulty temperature and pressure (T&P) relief valve
- Loose inlet/outlet pipe connections
- Failed drain valve
- Condensation on newer tankless units (normal)
- Cracked tank lining
How to Fix Leaking Water Heater: Step-by-Step
- 1Identify where the leak originates (top connections, T&P valve, bottom, or tank body)
- 2Turn off the cold water supply valve on top of the heater
- 3Turn off power (electric) or set gas to pilot mode
- 4Tighten loose fittings if visible and safe to reach
- 5Do not attempt to seal a leaking tank — it must be replaced
When Should You Call a Plumber?
Call a plumber immediately for any tank body leak. Same-day service is typically available for water heater replacement. Also call if the T&P valve is actively discharging — this is a safety device and its activation indicates dangerous pressure or temperature.
How Much Does Leaking Water Heater Repair Cost?
Average Cost $900
Typical Range $200 – $2,500
Costs vary by location, severity, and whether emergency service is needed. Prices shown are national averages. Get a free quote from a local plumber →
Frequently Asked Questions About Leaking Water Heater
- The drain valve is near the bottom of the tank, resembling a garden hose spigot. It's used to flush sediment from the tank. If it's leaking, it usually needs to be replaced by a plumber.
- The temperature and pressure relief valve is a safety device that opens if water gets too hot or pressure gets too high. Occasional dripping may indicate the valve is testing itself, but continuous discharge means excessive pressure or temperature — call a plumber today.
- Tank water heaters last 8–12 years. Tankless heaters last 15–20+ years with proper maintenance. Annual flushing to remove sediment extends tank heater life significantly. If your unit is over 10 years old and leaking, replacement is more cost-effective than repair.