Rheem Water Heater Leaking: Causes & Fixes

1. Loose or corroded inlet/outlet pipe connections

The hot and cold water supply connections at the top of the unit can work loose over time or develop corrosion, allowing water to drip down the side of the tank—often mistaken for a tank leak.

1. Turn off the cold water supply valve above the water heater.
2. Dry the area around both connections with a towel so you can clearly see where moisture originates.
3. Inspect the threaded fittings and flex connectors for visible corrosion, mineral buildup, or wet spots.
4. Use an adjustable wrench to gently snug any loose fittings—do not overtighten, as this can crack fittings.
5. If fittings are corroded or the flex connectors are damaged, replace them. Wrap all threads with fresh plumber’s tape (PTFE) before reinstalling.
6. Restore the water supply and check for drips after 10 minutes.

2. Faulty temperature and pressure (T&P) relief valve

The T&P relief valve is a critical safety component that releases water if pressure or temperature inside the tank gets too high. A worn or stuck valve will drip or discharge water from the discharge pipe on the side of the tank.

1. Locate the T&P relief valve—it is typically mounted on the side of the tank with a metal discharge pipe running toward the floor or drain.
2. Check whether water is dripping from the end of the discharge pipe or leaking around the valve body itself.
3. If water is dripping from the pipe, the valve may be releasing due to genuinely high pressure—check that the thermostat is not set above 120°F (49°C) and that a thermal expansion tank is installed if you have a closed plumbing system.
4. Carefully lift and release the test lever briefly (have a bucket ready)—if the valve continues to drip after releasing, it has failed and must be replaced.
5. To replace: turn off the water supply and power/gas, drain several gallons from the tank below the valve level, unscrew the old valve, wrap threads with PTFE tape, and thread in the new valve hand-tight plus one to two turns with a wrench.
6. Reconnect the discharge pipe, restore power/gas and water, and confirm no leaks.

3. Leaking or clogged drain valve

The plastic or brass drain valve at the base of the tank can develop a slow drip if sediment holds it partially open, if the packing washer degrades, or if the valve body cracks.

1. Confirm the leak is from the drain valve by drying the area and watching for drips at the valve spigot or where it threads into the tank.
2. Try attaching a garden hose and opening the valve fully, then closing it again—sometimes sediment is dislodged and the valve seals properly.
3. If the valve body still weeps, attach a standard hose cap to the spigot as a temporary fix.
4. For a permanent fix, turn off the water supply and power/gas, then connect a hose and drain the tank completely before unscrewing the old valve and threading in a replacement.

4. Condensation mistaken for a leak

On new units or in humid conditions, cold water entering the tank can cause condensation to form on the outside of the tank or on cold supply pipes, creating the appearance of a leak.

1. Dry the outside of the tank completely with a towel.
2. Wrap cold supply pipes with foam pipe insulation to reduce condensation on the piping.
3. Monitor the tank for 30–60 minutes; if moisture reappears on the tank surface only (not from a specific fitting or valve) and temperatures are cold or humidity is high, condensation is the likely cause.
4. Ensure the room is adequately ventilated. Condensation on a new gas unit typically disappears once the tank reaches operating temperature.

5. Anode rod port leaking

The sacrificial anode rod screws into the top of the tank and protects it from corrosion. If the anode rod was recently inspected and not resealed, or if the threads are stripped, it can become a slow leak point.

1. Locate the anode rod hex head on top of the tank (it may be under a decorative cover or plastic cap).
2. Dry the area and check for moisture specifically around the anode rod port.
3. Turn off the water supply and power/gas, then carefully tighten the anode rod with a 1-1/16 in. socket wrench.
4. If moisture persists, drain the tank below the anode port level, remove the rod, apply fresh PTFE tape to the threads, and reinstall. Replace the anode rod if it is more than 50% depleted.

6. Leaking or corroded tank (internal failure) — Rheem water heater leaking from the bottom

If water is pooling directly beneath the tank and no fitting, valve, or external component is the source, the inner tank lining may have corroded through—this is the most serious cause and the tank cannot be repaired.

1. Eliminate all other causes first by inspecting every fitting, valve, and connection as described in the steps above.
2. If you find water consistently forming at the very base of the tank with no external source, shut off the water supply and the power or gas to the unit immediately.
3. Do not attempt to repair a leaking tank—replacement is required.
4. Check whether your Rheem unit is still within its warranty period by locating the serial number on the data plate. Rheem’s warranty support page can help you decode the date of manufacture and file a claim: Rheem Official Support & Warranty.
5. Contact a licensed plumber to remove and replace the unit, ensuring proper disposal of the old tank.

Frequently asked questions

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