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How to Unclog a Water Heater That Won’t Drain (Detailed Guide)

Fact checked by Stephen Conklin

how to unclog a water heater that won't drain

Is draining the water heater taking a bit longer than it should? While a few factors can prolong tank emptying time, knowing how to unclog a water heater that won’t drain can put you back on track.

Draining a water heater is crucial in maintaining its optimum performance by removing mineral deposits and sediments. Unfortunately, these particles can also clog the hot water tank’s drain valve, preventing the efficient emptying of the system.

Worry no more because I will share some steps to unclog a water heater that refuses to drain.

Table of Contents

Things You Need for This Tutorial


The materials you need for unclogging a water heater that does not drain depending on how stubborn the obstruction is. In most instances, you only need ample time to drain the tank. Otherwise, you might want to prepare the following materials.

Hot Water Tank Draining Materials

Draining the water heater only requires a garden hose to facilitate water flow from the hot water tank to the floor drain or backyard. You might also need a small bucket and old towels to keep the work area dry.

Materials for Unclogging the Water Heater

A wire coat hanger or any stiff wire can help unclog the drain valve. If using this item fails, you might want to back-flush the water heater using a washer-fill hose. If it still fails, you can replace the drain valve with a new one; for your drain valve replacement, prepare some Teflon tape and a wrench.

Towels and a bucket

Steps for Unclogging a Water Heater that Doesn’t Drain


Step 1. Determine if you have a clogged hot water tank.

Clogging is one of the most common draining hot water heater problems anyone can encounter. Thankfully, religiously adhering to a maintenance schedule prevents drain valve obstruction issues. Sadly, not everyone has this mindset.

Hence, it would be best to determine if you have a tank drain valve obstruction.

Start by disconnecting the water heater power from the circuit breaker panel (for electric models) or shutting off the gas supply (for gas-powered units).

Get a garden hose and connect it to the drain valve, while positioning the other end outdoors or on a floor drain.

Turn on a hot water faucet to facilitate better drainage. Open the hot water tank’s drain valve and assess the water flow at the hose’s open end. If the water looks clear and is running steadily, there is no clog in the drain valve.

If the water flow is inconsistent or does not flow at all, you have a clogged drain valve.

Step 2. Wait a few hours to empty the tank.

In most cases, all you need is sufficient time to drain a hot water heater when it doesn’t drain.

Leave the water heater disconnected from its power source while leaving the drain valve open. Close the hot water faucet. Wait about an hour before checking the garden hose to see if it is already draining the water. If not, you might want to extend the waiting period for another hour.

Step 3. Loosen the clog with a stiff wire.

If Step 2 does not produce the expected results, you can try inserting a stiff wire (I recommend a wire hanger) through the drain valve opening to unclog the water heater drain.

Before you do this, it would be best to close the hot water tank drain valve and disconnect the garden hose. Next, place several towels on the floor below the drain valve and put a bucket on the towels.

Disassemble the wire coat hanger to create a long stiff wire. Open the hot water tank drain valve and push the wire through the opening and into the hot water tank.

Turn the wire as you inch through the drain valve or move it like you would with a drain auger. The twisting action should loosen any debris clogging the drain valve.

You should see the water coming out through the drain valve. Wait for a couple of seconds until you get a steady water flow before closing the drain valve again.

Reattach the garden hose, open the valve, and continue draining the tank.

eHow has an excellent video on how to perform the stiff wire technique.

Step 4. Stomp on the garden hose.

If the stiff wire trick does not solve the issue, you might want to stomp on the garden hose.

Stomping on the hose about two feet from the hot water tank creates a backward pressure that will dislodge whatever is clogging the drain valve.

This trick is most effective in a hot water heater clogged with sediment. It is like blowing through the pipe to force air into the hot water tank.

Unfortunately, this is a temporary solution because the sediment can still return to the drain valve and clog it again. In such cases, you have no choice but to keep stomping on the garden hose until you empty the whole tank.

Step 5. Back flush the water heater.

Back-flushing the water heater should help you solve the clogged drain valve issue if neither the stiff wire method nor the stomp-on-the-hose trick works.

You will need a washing machine fill hose for this step. Close the hot water tank drain valve and connect it to one end of the washer-fill hose. Next, extend the washer piping and secure its other end to a nearby faucet. You can also secure the second washer port to a garden hose running from a backyard tap.

Ensure the connections are water-tight to create sufficient water pressure before opening the faucet. Then, open the tank drain valve for about 15 seconds to push the obstruction away from the drain valve.

Close the faucet and the drain valve and disconnect the washer-fill hose from the water faucet. Open the drain valve, and continue draining.

Here is a video by ehowathomechannel showing how to backflush a water heater.

Step 6. Replace the hot water tank drain valve.

If the water heater doesn’t drain even after back-flushing the system, you might not have any other option than to replace the hot water tank drain valve.

Start by closing all water fixtures and faucets in the house. Next, prepare the new drain valve by wrapping Teflon tape around the threads.

Place a small bucket under the drain valve and use an adjustable wrench to loosen the old valve. Quickly remove the old valve and insert the new one as fast as you possibly can.

Connect the garden hose to the new drain valve, open it, and drain the water heater.


Learning how to unclog a water heater that won’t drain requires patience and a systematic approach. It would be best to start with less aggressive techniques before unclogging the drain valve with more forceful means.

Did you feel more confident about unclogging your water heater after reading this guide? If so, do you think your friends will also benefit from this tutorial? Would you share this with them? I will also be thrilled to receive your comments, questions, or feedback.

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