How to Drain a Hot Water Heater: DIY Guide

Explore our detailed guide on how to drain a hot water heater, designed to provide you with clear instructions and helpful tips for this crucial maintenance task.

Whether you're adept at DIY projects or just beginning, our guide offers a comprehensive walkthrough of the entire process, allowing you to discover how to safely and efficiently drain a hot water heater and ensure your water heater remains in optimal condition.

With our guide, you'll gain the knowledge and confidence needed to successfully manage this aspect of home maintenance on your own.

Draining a water heater - Things to consider

Highlights of the benefits

  • Remove or reduce the sediments
  • Extend the life of a heater and its elements
  • Keep the performance and efficiency high
  • Save money on the energy bills
  • Prevent future problems

Safety precautions

shutting the power off

Before beginning the draining process, it is vital to prioritize safety. The first step is to turn off the power supply to the water heater.

For electric heaters, this means switching off the circuit breaker, while for gas heaters, the gas supply should be turned off. This precaution is necessary to prevent accidents, such as electrical shocks or gas leaks.

Additionally, ensuring that the area around the water heater is clear and free of any obstacles or flammable materials is crucial. A clear workspace not only provides easy access to the heater but also minimizes the risk of injuries or accidents during the draining process.

Required tools and materials

  • Pipe wrench
  • Adjustable wrench
  • Garden hose
  • Bucket
  • Screwdrivers
  • Multimeter
  • Teflon tape

How to drain a hot water heater: Instructions and video included

closing the water valve

This guide is made for standard tank-type gas water heaters. Keep in mind, these are a bit different from electric water heaters. We'll focus on what's unique about gas models, so you can safely and correctly take care of them.

  • When draining your water heater, start by turning off the unit completely. This means shutting off the power supply - for gas heaters, turn off the gas valve, and for electric heaters, switch off the circuit breaker. Also, don't forget to turn off the water supply to the heater.
  • Next, attach one end of a garden hose to the heater's drain valve. Place the other end in a suitable location, like a floor drain or outside, where it can safely dispense hot water. A garden hose is typically more convenient and effective than using a bucket.
  • Before you start draining, open a hot water tap closest to the heater. This step prevents a vacuum from forming inside the tank, which can impede water flow. Also, open the Temperature Pressure Relief (TPR) valve to release any built-up pressure in the tank.
  • Let the hot water run from the tap until it reaches 100 F or less to avoid scalding burns.
  • Open the drain valve and allow the water to drain out.
  • Keep in mind that it will take some time to drain all the water, especially if the tank has a capacity of 50 gallons or more.
  • After the tank is empty, flush it out by opening the cold water tap. This helps remove any remaining sediment. Keep flushing until the water running out of the drain valve is clear.
  • Once you're done, close both the drain valve and the TPR valve. Refill the tank by reopening the water supply. Ensure the tank is completely full before moving to the next step.
  • For gas heaters, follow the manufacturer's instructions to relight the pilot light. For electric heaters, turn the power back on by flipping the circuit breaker.

Note: Always ensure the tank is full of water before restoring power or lighting the gas burner. Turning on the heater with an empty or partially filled tank can cause damage to the heating elements and gas burner.

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The importance of draining your hot water heater

Removing the sediments

There are many reasons to drain a water heater, and one is the most important: to get rid of the debris, sediment, and lime build-up from the bottom of the tank.

Mineral deposits at the bottom of the tank and on the heater's elements could prevent regular heat transfer between the gas burner or electric elements and water. This leads to lower efficiency and reduced performance, and frequent user complaints such as “no hot water”, “not enough hot water”, “low pressure” and such.

Also, the sediments can block the drain valve, which will make draining much harder or even impossible.

Heavy mineral deposits could eventually result in water heater replacement as there is no fix for such a problem. Those who live in the area with hard water should drain the unit often, even if the heater is equipped with the "self-cleaning" systems.

To prevent the effects of hard water and reduce the risk of sediment buildup, install a water softener. The softener will remove the hardness minerals, improve efficiency, prevent future problems and make the unit last longer.

Preventing leaks and freezing

Drain valveDrain valve

It is necessary to drain a water heater when the tank is leaking, when removing the old unit or doing some major service on the unit.

If you have to replace an anode rod or a dip tube, you should drain only a few gallons of water. In contrast, on some models when replacing a gas control valve or electric heating elements emptying the entire tank is necessary.

Another reason for draining is to prevent the heater from freezing or when winterizing the unit. In this case, the whole tank should be emptied, including the plumbing pipes.

How often to drain a water heater

Draining a water heater should be part of the regular maintenance and is recommended by every manufacturer as well as experienced plumbers.

Draining and flushing the heater's tank should be performed once or twice a year, especially in areas with hard water.

More tips

Note: The heater should have easy access for operation, maintenance, and service.

Some storage-tank heaters are equipped with a plastic drain valve, while others use a more reliable, tamper-resistant brass drain valve. The thread size is the standard 3/4 inch, and they come installed on the unit. Some plumbers recommend installing ball valves instead, for simpler draining and longer life.

If you flush a water heater regularly, you won't see much discolored water. However, if you haven't flushed a water heater for a long time, be prepared to see brown, rusty water and other deposits. These can come from sediment and limescale buildup or corrosion.

Regularly draining the hot water heater can significantly extend its operational life and efficiency, while also reducing costs.

Warnings about common mistakes and how to avoid them

When maintaining a water heater, it's crucial to be aware of common mistakes and take steps to avoid them.

One frequent error is neglecting to completely shut off the power or gas supply before starting any maintenance work, such as when you need to drain a hot water heater. This oversight can lead to serious safety hazards. Always ensure that the power, whether it's electricity or gas, is entirely disconnected.

Another mistake is not allowing the water to cool down sufficiently before attempting to drain a hot water heater, which can cause scalding injuries. Give the heater ample time to cool after turning it off.

Additionally, improper handling of the pressure relief valve is a common oversight. This valve should be opened before draining to prevent a vacuum from forming in the system, which can cause damage.

Lastly, failing to properly secure the drain hose can lead to leaks and water damage. Ensure the hose is firmly attached and directs water to an appropriate draining area. By being mindful of these pitfalls, you can safely and effectively maintain your water heater.

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