Water Heater Drain Valve Stuck: The Possible Reasons and Solutions

Water Heater Drain Valve Stuck

The drain valve in the water heater is used to remove residual build-up inside the drain. You will use it to repair the drainage, and replace the damaged valve. Usually, lime, calcium, and mineral residues will develop around the drain valve. It forces the drain valve to stop moving and working.

In short, residual and debris build-up causes water heater drain valve stuck occurrence. When the valve gets stuck and eventually clogged, you need to unclog it. At times you might need to replace the drain valve of the water heater.

We will, therefore, discuss the ways to remove a clogged and stuck drain valve. We will show you ways to replace the water heater drain valve without draining. So, continue reading the article if you have issues with the water heater drainage.

Water Heater Drain Valve Stuck: Possible Reasons And Solutions Explained

Imagine you have decided to clean and flush off the draining pipe of the water heater. Then, you start working and see the drain valve isn’t coming off properly. Thankfully, you can fix the problem of the drain valve won’t come off properly at home.

First, you need to know the reasons for a stuck water heater drain valve for it.

Mineral and residual development:

Usually, minerals in the water will slowly develop around the draining pipe and the valve. It includes lime, calcium, etc. So, the residues will force the drain valve from moving properly. The gradual development of hard water residues within the pipe will cause clogs.

Unfortunately, you can’t skip this problem. In fact, it is even more acute in hard water regions that comprise 85% of American localities. The only thing you could do is remove the residues from the stuck drain valve.


You must eliminate the debris to unclog the pipe and fix the residual development problem. You will need to remove the stuck drain valve first. After that, clean its surroundings and unclog the pipe. You may use a draining snake or auger, to unclog the pipe.  

Alternatively, you can flush off the pipe with white vinegar and baking soda to help it work properly.

Damaged drain valve:

A damaged drain valve will also get stuck. The damage mainly happens as you use the drain valve for years. Also, the water heater plastic drain valve will get damaged more than the metal ones. Rust and corrosion cause the damage.


If the water heater drain valve is damaged, you need to replace it. You can replace the water heater drain valve with a few DIY steps without draining.

How to Repair And Change Damage Drain Valve

A stuck drain valve of the water heater will clog the draining system. Thus, you will need to remove the clogs. Also, you may see a hot water heater clogged with sediment. At that time, you must flush off the sediments to help it work appropriately.

You will need:

  • Leather-palm gloves
  • Pipe wrench
  • Hose
  • Washer hose
  • Screwdriver
  • WD-40 cleaner

Method 1: Observe and prepare the water heater draining process

You need to observe why the water heater isn’t draining. Try to find whether it’s stuck due to damages or residual build-ups. Moreover, check if the draining pipe is clogged. Then, you may start working with the stuck water heater valve.

Firstly, turn and align the gas valve perpendicularly with the gas pipe. You will need to attach a drain hose with it. It connects the valve with the nearest draining spot such as floor drain.

If the drain valve isn’t stuck, you can easily drain the water heater with this technique. At this point, it might seem that draining the water heater is easy. However, you can’t always drain the clogged water heater as easily as this “Method 1.”

During this time, you need to move to the next method.

Method 2: Repeatedly step on the drain hose

You need to create an air bubble inside the tank to drain it forcefully. So, step on the drain hose of the heater. You need to stand around 2 feet away from the water tank.

Standing on the hose creates an air bubble within the tank. It then forces the tank to eliminate the residual and mineral development. You will have to repeat the process multiple times to unclog the water heater.

Method 3: Opening and removing a stuck drain valve of your water heater

Observe to see whether it has been damaged due to corrosion, or residual development. Then, try removing it with an adjustable wrench. Hold on to the valve with the wrench. Now, pry it off from the attached point. You will need to replace the water heater drain valve after removing the older one.

Nonetheless, you need to remove the debris if residual development is causing the problem. For this, apply commercial WD-40 cleaner around it. After that, wait for a few minutes and flush off the debris with cold water.

Next, attach the hose with the drain valve as you open it. Now, open the pressure relief valve or turn off the water heater. It helps the water heater drain with the negative pressure not inside the tank anymore.

Tips on how to open a water heater drain valve:

You must turn off the water heater before attempting to unclog the heater. Then, wait for 24 hours to allow the heater to cool off properly.

Connect the wrench with the valve and start turning it gradually. You will see the water heater drain valve dripping when you unscrew the valve. Water will pour through the draining pipe as you remove the stuck drain valve. It will help the water heater to remove the clogs fully.

You may see lime development at the mouth of the valve after removing it. Thankfully, you can remove the lime development by swirling a screwdriver inside the valve’s mouth. You need to repeat it multiple times to unclog the drain.

Tips On Ways To Replace Water Heater Drain Valve Without Draining

You might try back flushing the water heater to drain it. However, you must replace the drain valve after removing it.

  • Buy a new drain valve for the water heater. You should choose a brass drain valve because it won’t catch rust and corrosion.
  • Before proceeding, ensure you have turned off the water supply line. Thus, there will be a vacuum inside the heater, and water won’t drip from it.
  • You may follow our steps to open and remove the stuck valve. We have described it in the previous section.
  • Before you mount the new valve, wrap its threads with Teflon tape.
  • You may clean off inside the pipe using a draining snake or auger. It will help you clean the debris from inside the pipe also.
  • Alternatively, you can pour baking soda and white vinegar inside the pipe and flush it off with hot water after a few minutes.
  • Now insert and mount the new drain valve. After that, you might connect the drain hose to drain the heater once again.

Frequently Asked Questions:

Can you remove the plastic drain valve from the water heater?

Yes, you can remove the plastic drain valve of the water heater. Nonetheless, it can be tricky, so you must be cautious to avoid damage to the plastic valve, or else you need to replace it.

How much does it cost to replace a drain valve?

Usually, a drain valve will cost you around $50 to $200. Also, fixing a leaky drain valve of the water heater will cost approximately $50.

Are all water heater drain valves the same size?

The standard drain valve size for a water heater is ¾ inches. Thus, it is safe to say that all water heater drain valves come in the same size.


When you see the water heater drain valve stuck, you don’t need to be panicked. When you see the water heater drain valve won’t come off easily, you can replace it. You have to turn off the water supply lines and unclog the drain before replacing the stuck drain valve.

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