Rheem Water Heater Drain Valve Replacement - Signs & How-To

Rheem Water Heater Drain Valve Replacement — What This Part Does

The drain valve sits at the bottom of your Rheem tank and lets you empty water for maintenance or flush out sediment that builds up over time. Factory plastic valves crack, leak around the threads, or seize shut after years of mineral exposure and thermal cycling.

Rheem sells both plastic and brass replacement drain valves as service parts for draining and sediment flushing on Rheem, Ruud, and Richmond tanks. Most techs upgrade to brass because it resists cracking and seals better under the 60 to 80 psi municipal supply pressure that remains in the tank until you relieve it.

Jump to Replacement Steps

Signs It Needs Replacing

• Steady drip or puddle under the valve Water leaks from the valve body or threads even when the handle is fully closed.
• Cracked or brittle plastic valve body You see visible cracks in the plastic housing or the valve body feels loose on the threads.
• Valve won’t turn or is seized shut The handle is frozen in place and you can’t open it to drain the tank for flushing.
• Valve won’t close after draining After you finish draining sediment the valve continues to leak because the internal seal is worn out.
• Slow or restricted flow when you try to drain Sediment has clogged the valve opening so flushing the tank takes hours or doesn’t work at all.
• Corroded threads or mineral buildup around the valve White or green deposits coat the valve and you see rust or corrosion where it threads into the tank.

How to Replace It

1. Turn off power at the breaker (electric) or set the gas control to Off (gas heaters) and shut off the cold-water supply valve feeding the tank.
2. Open a hot-water faucet somewhere in the house and lift the lever on the temperature-and-pressure relief valve at the top or side of the tank to relieve pressure until water stops flowing.
3. Verify that the cold-water shutoff actually stops flow by cracking open the old drain valve briefly. If water still sprays out under pressure, fix or replace the upstream shutoff first.
4. Attach a garden hose to the drain valve and run it to a floor drain or outside, then open the valve fully and let the tank drain until water stops or slows to a trickle.
5. Use a pipe wrench or adjustable wrench to unscrew the old drain valve counterclockwise. Be ready for residual water to spill out as you remove it.
6. Wrap the threads of the new brass drain valve with three to five turns of Teflon tape in a clockwise direction, then hand-tighten the valve into the tank opening.
7. Snug the new valve with a wrench, turning it about one additional turn past hand-tight. Do not overtighten or you risk cracking the tank threads.
8. Close the new drain valve handle, remove the hose, and open the cold-water supply to refill the tank. Watch for leaks around the new valve threads as pressure builds.
9. Restore power or relight the pilot (gas) and check that the new valve remains dry under full pressure once the tank is full and hot.

The Part You Need

Related Error Codes

If this part is failing you may also see one of these codes:

• Rheem Water Heater A01 error code
• Rheem Water Heater Alarm 401 error code

When to Call a Pro

If you cannot shut off the cold-water supply or the upstream shutoff valve leaks, call a plumber to replace that valve before you touch the drain valve. If the tank itself is leaking from the bottom seam or you see rust and corrosion around the drain opening in the steel, the tank is failing and a pro should evaluate whether replacement makes more sense than a valve swap. For gas heaters, if you are not comfortable relighting the pilot or checking for gas leaks after the repair, have a licensed tech complete the startup and safety checks. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.