Why Won’t My Water Heater Drain?
TechXpert verified by Rob Ilie
A clogged drain valve, a faulty water heater drain valve, or sediment buildup in your water tank could prevent your water heater from draining. There are a few common issues that can stop your water heater from draining. Think you’ve got a clog? Here’s what to do to diagnose and fix your drain problem.
Reasons Why Your Water Heater Won’t Drain
A few things can stop the flow of water. The solution will depend on the issue at hand, so that’s where you should start.
Clogged or Blocked Drain
All sorts of dirt and debris can build up in drains over time, and if your water heater isn’t being flushed regularly, you can expect the sediment and calcium to clog the drain valve. If this is the case, you’ll need to clean the drain to get things back on track.
Faulty Water Heater Drain Valve
A defective water heater drain valve will prevent you from flushing or draining your water heater as recommended. It’s difficult to clear a clogged water heater drain, and it’s not an easy repair -- more often than not, you’ll need to have the valve replaced.
Sediment or Mineral Buildup in Your Water Tank
Just as dirt and debris can build up in your drain, sediment or minerals can build up in your water tank. Naturally occurring minerals like calcium and magnesium can start to settle and accumulate in your system over time, and eventually will begin to block the drain opening on your water heater.
Now What? Unclogging Your Water Heater
In the case of a slow-draining water heater, sometimes the clog has a way of working itself out. As the water heater tries to drain, there’s a chance that it will just push the clog through. Give it an hour or two, then check back on your water heater to see if the issue has resolved itself.
Give it a Little Poke
If some kind of debris is lodged in your water heater drain valve, you might be able to poke it out:
Put some towels or a bucket beneath the main water valve to catch any water flow or the debris, and open the valve.
Using a thin and sturdy wire (such as a straightened out wire hanger), slowly insert and make a circular motion within the drain pipe to push out the clog.
A word of warning: be prepared to turn the valve off immediately if the valve starts to drain!
Sometimes a bit of pressure is enough to force out the clog. Try kinking the hose attached to your water heater — this change in pressure might clear the blockage and get your water heater draining again.
You can also turn the water heater main shut-off valve off and back on again to change the pressure and help loosen the debris.
Have Your Water Heater Flushed
If your system is backed up with debris, sediment, or minerals, it’s a good idea to have your water heater flushed. Contact your local plumber to learn more about the process and to schedule an appointment.
Time For a Valve Replacement
Still stuck with a drainage problem? If unclogging the drain didn’t do the trick, there might be too much buildup and damage to your valve. In this case, a new water heater drain valve is the key to your repair, and that’s where a professional plumber can help.
FREE Virtual Home Repair
We'll diagnose your issue over call or video and virtually walk you through the repair — all for free if you're a new customer! .