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How to Drain a Water Heater Fast in 8 Surprisingly Easy Steps

Fact checked by Stephen Conklin

how to drain a water heater fast

Is this your first time draining your water heater, but you are unsure how to drain a water heater fast enough not to disrupt your family’s hot water needs? If you are methodical in your approach, draining a water heater should not take more than an hour, including other related activities.

Draining a water heater is an essential maintenance activity. It allows you to remove mineral deposits from the tank’s bottom and clean it to maintain its water heating performance.

In this article, I will show you how to drain the hot water tank quickly.

Table of Contents

Things You Need for this Tutorial


Draining a water heater does not require many tools or materials.

  • Water Hose

Emptying a water heater as quickly as possible requires no more than a garden hose to convey the water from the hot water tank to the drainage area. You can use any flexible pipe for this procedure, as long as you can connect it to the tank’s drain valve and run it to a floor drain or into your backyard.

  • Hand Tools

Unfortunately, some valves can be challenging to turn by hand. Hence, you might want to prepare a vise grip to create an improvised lever for opening and closing the valve. Using a flat-tipped screwdriver also helps.

  • Old Towels

Having old towels or pieces of rags can help minimize mess. You can place these materials underneath the drain valve and the garden hose’s entire length. It should prevent puddles from forming and reduce the amount of cleanup after the process.

  • T&P valve (optional)

If you intend to replace a defective temperature and pressure (T&P) relief valve, it would be best to have the replacement on hand before you drain the water heater.

  • A pan (optional)

Steps for Draining a Water Heater Quickly


Step 1. Check the water heater’s T&P valve.

You can proceed to Step 2 if your water heater is less than a year old.

The temperature and pressure (T&P) relief valve is an essential component of any hot water tank. The small device accommodates excess steam and pressure from the hot water tank because of thermal expansion.

Check the T&P valve’s location, usually on the tank’s top or the upper side. It has a tube – the discharge pipe – running down the tank.

Place a small pan underneath the discharge tube’s open end and open the T&P valve only slightly to release pressure. You should hear a hiss (similar to venting the steam on a pressure cooker).

If you hear the sound, you can close the T&P valve and proceed in draining electric water heater or gas water heater.

If there is no hiss or no water droplets at the discharge tube, forget draining the water heater for now. It would be best to schedule the draining when you already have a T&P valve replacement.

Step 2. Turn off the gas or electric power to the water heater.

If the T&P valve is functioning properly, you can start with the process of draining the water heater.

The first step involves turning off the fuel or power supplying the water heater. Gas water heaters connect to a gas supply line with a shutoff valve. Locate and turn off the gas supply shutoff valve.

Most electric water heaters have a direct connection to the household’s electrical lines. Head to the circuit breaker panel and look for the section marked ‘water heater.’

It would be best to turn off the whole electrical panel if you cannot see the label or are unsure which breaker cuts off the power to the water heater.

Step 3. Let the hot water cool off.

Never drain electric water heater or gas water heater as soon as you cut off the power or fuel supply. It would be best to wait for the water to cool down a bit to prevent burn injuries.

You can hasten the cooling process by opening a nearby hot water faucet. Do not close the main water supply valve yet because you need cold water to flow into the tank as the hot water flows out of the open water faucet.

Step 4. Prepare the drain hose.

Get your garden hose and locate the water heater’s drain valve. You should be able to see it at the hot water tank’s bottom section, complete with a lever for opening and closing the valve. In case of without drain valve you can read this guides to drain the water heater most efficiently.

Connect the garden hose to the drain valve’s spigot and extend it outdoors in your backyard. Alternatively, you can position the flexible tube’s open end on a floor drain.

Pro Tip: Always straighten the garden hose from the tank to the drainage space if you want to drain a hot water heater quickly.

Step 5. Close the cold water supply to the water heater tank.

After several minutes of free-flowing water through the tank, it should be safe enough to drain the water. I recommend checking the water coming out from the hot water faucet. It should not be too hot.

Check the water pipe going to the hot water tank’s top and see if it has a shutoff valve. Turn this valve off to prevent cold water from entering the tank.

If you do not see a shutoff valve, try following the water supply line and locate a shutoff valve. Most households have a master shutoff valve at the main water supply line. Shut this valve off.

Step 6. Empty the tank.

Fully open the hot water tank’s drain valve to start emptying it. You might want to check the garden hose’s open end to assess whether the water is flowing continuously or not.

If you notice inconsistent flow, you might want to check the tubing for kinks. Straighten the hose to facilitate faster drainage.

In general, a water heater drains at an average of nine to seventeen gallons per minute. You can use this rate to calculate how long you must wait to empty the hot water tank.

For example, if you have a 40-gallon tank, you can expect to empty the water within 2.3 to 4.4 minutes. It should be sufficient time for you to grab a cup of coffee, read the headlines, or listen to your favorite song.

Pro Tip: Leave the hot water faucet open during this time to drain water heater faster.

Step 7. Refill the hot water tank.

Close the hot water tank’s drain valve and disconnect the garden hose. Roll the flexible tubing and put it back where you got it.

Turn off the hot water faucet and open the cold water supply shutoff valve. Wait several minutes to fill the water heater tank. Refilling the tank can take anywhere between 30 and 70 minutes, depending on the tank size, water pressure, and water flow rate.

After refilling the tank, open the hot water faucet then close it when you see no air bubbles.

Step 8. Reestablish power or gas supply to the water heater.

Turn on the gas shutoff valve and light the pilot light. If you have an electric water heater, head to the breaker panel and switch on the water heater circuit breaker.

Depending on your water heater, it can take 30 to 40 minutes to heat the water to the ideal temperature. The rate of water heating depends on the cold water temperature and the level of temperature rise.

Here is an excellent video from MonkeySee about draining a water heater.


Learning how to drain a water heater fast entails cooling the hot water quickly and straightening the drain hose. While the actual emptying process does not last more than ten minutes, the preparatory activities and the waiting game can make tank emptying seem like forever.

Did you find this guide beneficial? Do you think other people will also appreciate it? If so, would you share this tutorial with them? I also look forward to any comments, feedback, or questions you might have.

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