Rheem Water Heater Leaking — What’s Happening
A Rheem water heater leaking is a physical symptom, not an error code. On storage tank models, the leak can come from the temperature and pressure relief valve, piping connections, tank corrosion, or a component seal. On tankless units, the issue is often condensate discharge or internal water from a blockage or component failure.
Rheem troubleshooting materials treat leakage separately from electronic codes. Some water discharge from the T&P valve is normal during heating, but it should be about 1/50 of the hot water used. More than a bucket in 24 hours points to a problem with pressure, expansion, or the valve itself.
Most Likely Causes
- T&P relief valve discharge from excess pressure or thermal expansion High system pressure or lack of expansion control forces water out through the relief valve, which is the most common leak source on storage heaters.
- Loose or failed piping connections Unions, inlet/outlet nipples, flex connectors, and drain valves can develop leaks at threads or gaskets over time.
- Faulty temperature and pressure relief valve The valve itself can fail internally and drip or discharge even when system pressure and temperature are normal.
- Tank corrosion or internal tank failure A leaking steel storage tank from rust or seam failure is not repairable and requires water heater replacement.
- Condensate drain blockage on tankless or hybrid models Blocked condensate drainage or internal seals can cause water to leak from the unit cabinet or drain path.
- Failed drain valve or gasket The plastic drain valve at the bottom of the tank can crack or leak at the seal, especially after being opened for maintenance.
How to Diagnose and Fix
- Identify the exact leak source by inspecting the top connections, side seams, bottom pan, drain valve, T&P relief valve outlet, and any condensate drain path.
- Confirm whether water is coming from the T&P relief valve discharge line, then check for overtemperature, excess system pressure, or expansion issues.
- Measure incoming water pressure and verify whether the system has proper expansion control (expansion tank or other device) if required by local code.
- Inspect and tighten all accessible pipe connections, unions, flex lines, dielectric nipples, and the drain valve.
- Check for tank failure by looking for water seeping from the tank shell, seams, or bottom pan (if present, plan for replacement).
- For tankless or hybrid units, inspect condensate drainage components, clear any blockages, and verify proper drainage before replacing parts.
- If the leak is from a failed T&P valve, drain valve, or seal, replace the component and retest under heat and pressure.
- After repair, monitor the unit through at least one full heating cycle to confirm no further discharge or dripping.
Parts You Might Need
| Part | Notes |
|---|---|
| Temperature and pressure relief valve | Amazon | 3/4-inch threaded, rated to match tank pressure (typically 150 psi) |
| Drain valve | Amazon | Plastic or brass, 3/4-inch threaded base |
| Expansion tank | Amazon | Sized to system volume if thermal expansion is causing relief valve discharge |
| Pipe unions and flex connectors | Amazon | Replace if threads or gaskets are worn or leaking |
Related Error Codes
If your appliance also shows a code on the display, these match this problem:
When to Call a Pro
Call a licensed plumber if you see water seeping from the tank body or seams, since that means tank failure and full replacement. Also call for help if the leak is from the T&P valve and you are not comfortable testing system pressure, checking expansion control, or replacing the valve. For tankless or hybrid units with internal leaks or condensate issues, a pro can diagnose drainage blockages and component seals safely. Any work involving gas lines, burner removal, or internal access on gas-fired units should be handled by a qualified technician. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.