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How to Unclog a Water Heater That Won’t Drain in 5 Simple Steps

Writen by Ronald Brown

Fact checked by Natalie Bridges

how to unclog a water heater that won't drain

Are you tired of the draining hot water heater problems? So am I! Diagnosing what is technically wrong inside our water heaters is a challenging task. If your water heater won’t drain properly, you might have a clogged drain valve.

If the draining performance of your water heater is declining, learning how to unclog a water heater that won’t drain will help you restore the maximum efficiency of your water heater.

All you have to do is prepare the essential tools and accessories to mitigate the sediment build-up that prevents your water heater from running at its best. Moreover, I will share easy-to-follow steps later in this article.

Table of Contents

What Will You Need in This Tutorial


Troubleshooting water heaters at home could test our patience at times, but you do not have to get worked up with this small-scale DIY project. Just prepare the following household supplies to unclog water heater drain like a pro :

  • Garden Hose – A conventional garden hose (3-4 ft long) with a correct fitting is all that you need. It is for hooking up with your water heater drain valve to dislodge the sediments and water on your water heater tank.
  • Household Bucket – A large bucket is indispensable for this task because it will collect the water and mineral deposits coming from your drain hose.
  • Wire Coat Hanger / Scrap Metal Wire – A steel wire is handy to unclog the drain valve that may be impeding the flow of water.
  • Cleaning Towel – As you clean the valve, water will come through. Hence, it is always necessary to have a dry cloth to clean and absorb the mess.
  • Drain Valve Replacement and Accessories – Your drain valve gets clogged with sediments over time and it is highly possible to have a damaged or worn-out valve after quite some time. Include an adjustable wrench and Teflon tape in your replacement kit.

How to Drain a Hot Water Heater When It Won’t Drain?


There are different methods on how to fix a hot water heater clogged with sediment build-up, but I will walk you through the most straightforward steps to do it :

Step 1: Turn off the power and cold water supply of your water heater.

Flip the circuit breaker of your electric water heater to the OFF position from your electric panel. For gas units, shut off the temperature dial at the top of the thermostat. Turn the dial from the PILOT to the OFF position.

Next, go to the cold water supply valve of your water heater. It is a single-handed valve located at the top of your unit. Turn it 90 degrees from its open position. If you find a circular valve, twist it clockwise until it closes.

Step 2: Determine if you have a clogged drain valve.

Secure the hose to the drain valve. Direct the other end to the bucket as a draining reservoir. Use an adjustable wrench to tighten the nuts of the hose to avoid leakage while draining.

Then, open the nearby hot tap water to relieve the pressure. Turn on the drain valve. It may look like a small outdoor faucet. If your drain valve does not have a lever/knob, use the flathead screwdriver to open it. Place it in the screw slot and twist it until it opens.

Go to the bucket and inspect the water gushing out from the hose. If it runs clear and has steady flows, you have no problem with the drain valve. But if the water trickles or does not stream at all, your drain valve is completely clogged.

Pro Tip: This is a hot water draining method. Hence, it is safer to wear protective clothing to avoid hot water scalding.

Step 3: Let the drain valve open for an hour.

Wait for an hour to get water to flow through the drain hose. If the sediment build-up is just too severe, expect to wait for about a few hours.

Pro Tip: If your drain valve is not completely clogged, just let your drain valve release as much water as it can. It will allow the cold water to circulate and dilute the hot water.

Step 4: Prepare the thin metal wire and slip it over the drain outlet.

If you still have the same problem, prepare to unclog your jammed drain valve using your readily available wardrobe wire hanger. Straighten it out and create a small hook. It will be like your DIY drain auger snake. Before using it, you must disconnect the garden hose and close the drain valve in the meantime.

Then push the wire slowly down the drain opening and start fishing. Swirl the wire around to capture the lingering dirt and debris. You can move the wire back and forth to the drain valve to quickly transport large amounts of sediment blocking the water pathway.

Do not forget to place a towel beneath the drain valve to clean up any water and debris. This trick would help in a minor clog. Suppose a sediment build-up occupies a large portion of your tank. The sediment formation may recur. Hence, it is not a permanent remedy.

Pro Tip: If you still have a hard time draining the tank, step on the hose firmly a couple of feet away from your water heater. It will allow compressed air to enter the tank and force the debris and water through the drain line.

Step 5: Backflush your hydronic tank.

To do a backflush, buy a male-to-female garden hose adapter in the hardware or specialty stores. Screw one end of the female hose connector onto the male end of your garden hose and attach the other end to the outdoor faucet or any nearby tap water.

Reattach the other end of the hose to the drain valve (the one we removed previously) and run it on the bucket before opening the faucet. Next, reactivate the drain valve for 15 seconds.

The back-flowing cold water will then run through the hot water lines and loosen up the mineral deposits. Let your water heater flush until you no longer see any sediment mixing with water. After that, close the faucet and the drain valve.

Pro Tip: I prefer using a female coupler because it is cost-efficient, but you can also use a washing machine fill hose because it has female threads on both ends.

What to Do if the Water Heater Is Still Refusing to Drain?

If the problem persists even after completing the procedures, you need to replace the drain valve:

  • First, wrap around two-three layers of Teflon tape around the threaded nipple of your new drain valve.
  • Position the bucket under the old drain valve. Use the adjustable wrench to remove the damaged valve. You will then see water dripping as you detach it.
  • Mount the new drain valve. Use the same wrench and screw the brand-new valve clockwise.


A clogged water heater requires immediate repair to reduce its costly consequences. Hence, it remains one of the top nuisances that we homeowners deal with every day.

Luckily, you just uncovered the helpful tricks on how to unclog a water heater that won’t drain! This incredible skill will benefit your maintenance journey in the long run. For any questions and suggestions, feel free to speak your mind in the comment section!

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