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How to Drain a Rheem Water Heater? – 8 Simple Steps

Fact checked by Stephen Conklin

how to drain a rheem water heater

Learning how to drain a Rheem water heater is an essential aspect of water heater ownership. After all, every homeowner will want this appliance to function optimally.

The water going to a Rheem Performance water heater or any variant might contain sediments, particulates, and other substances that accumulate at the tank’s bottom.

Keep reading to learn how to drain the water from your Rheem model as part of routine maintenance.

Table of Contents

Step-by-step Guide for Draining a Rheem Water Heater

What to Prepare

You only need a garden hose in this Rheem water heater maintenance. A bucket and some rags should also be handy to minimize mess.

Step 1. Read instructions.


Start by reading model-specific maintenance recommendations and instructions.

For example, you can check the Rheem Guardian water heater manual to learn the detailed steps for draining and maintaining the unit.

It is worth noting that Rheem Guardian is a commercial-grade system with unique maintenance requirements.

Hence, reading Rheem water heater flushing instructions beforehand should make this activity more straightforward.

Step 2. Disconnect the Rheem water heater from its power source.


Go to the electrical panel in your home and locate the circuit breaker connected to the water heater. It should have a corresponding label, so you will not miss it.

Turn off the circuit breaker to the water heater.

Follow the gas pipeline connected to the water heater if you have a gas-powered Rheem unit. Look for a shutoff valve next to the water heater’s lower front section.

Turn off the shutoff valve to the Rheem water heater.

Step 3. Stop water flowing into the water heater.


Follow the cold water supply line entering the Rheem water heater and look for a shutoff valve. Turn the handle or knob clockwise to prevent water from entering the unit.

Step 4. Leave the water to cool off.

This step is crucial before you open drain valve on Rheem water heater.

Understand that the water in the storage tank could have a temperature of 120 to 140 degrees Fahrenheit. Although it is lower than the boiling point, you can still injure yourself if you do not wait for the liquid to cool down.

You can schedule the flushing in the early morning to allow the water heater to cool overnight. Alternatively, shower so there’s less hot water in the unit.

Step 5. Drain the water from the water heater.


Locate the Rheem hot water heater drain valve and connect a garden hose to it, ensuring a tight fit to minimize leaks during draining.

Position the hose’s open end next to a floor drain. If the flexible pipe is long enough, you can extend it to the garden.

Locate the closest hot water faucet to the Rheem water heater and open it. This step facilitates faster draining by reducing pressure within the system.

Open the Rheem water heater drain valve by turning the handle counterclockwise.

Be patient because it takes time to empty a storage tank. For example, a Rheem 50 gallon water heater might take three to six minutes, depending on the water pressure and garden hose diameter.

  • Pro Tip: You can place a bucket underneath the water heater drain valve-garden hose connection to catch any dripping water. Surrounding the bucket with rags should also minimize mess.

You can also quicken the drain time by opening the cold water shutoff valve. The water’s added weight should help push it through the hose.

Step 6. Let the water flow to the water heater.


Open the cold water shutoff valve without closing the water heater drain valve and the hot water faucet.

This action will help remove particles inside the water heater storage tank.

Watch the water coming out of the garden hose. You can stop flushing if the water looks clear.

Step 7. Fill the water heater tank with water.

With the water running clear, close the drain valve and wait until no more water comes out from the hose. Do not forget this step to avoid spilling water onto the floor.

Keep the cold water shutoff valve open and fill the water heater storage tank.

Watch the water flowing through the hot water faucet. You can close this water fixture if the water flow is steady and continuous.

Step 8. Reestablish power to the Rheem water heater.

You can turn on Rheem water heater as soon as the storage tank is full.

If your water heater is an electric model, switch on the circuit breaker at the electrical panel. For gas units, reignite the pilot light or open the gas shutoff valve.

You might want to refer to the manual for specific instructions on reestablishing power to your Rheem water heater.

Frequently Asked Questions


What is the fastest way to drain a Rheem hot water heater?

Opening a hot water faucet near and above the Rheem water heater can make it drain faster.

Alternatively, you can open the water heater drain valve for two to three seconds before closing it again to create a pressure differential.

How long does it take to drain a Rheem water heater?

The drain time of a Rheem water heater depends on the storage tank size, water pressure, and garden hose size.

For example, a 50-gallon unit might empty its contents within three to six minutes. At most, 30 minutes to an hour should suffice for larger tanks.

Do I need to flush a Rheem tankless water heater?

Yes, a Rheem tankless water heater flush is necessary to keep it in optimum working condition by removing mineral deposits that may have built up over several months.

A tankless water heater has no drain valve, but it has isolation valves to facilitate flushing. Some models come with plastic valve units, so homeowners must be cautious when handling these parts.

Related post: 4 steps to drain a water heater without a drain valve.


Learning how to drain a Rheem water heater is not as challenging as some believe. It only requires a few materials and several steps to complete the task.

However, the process could be longer if the water heater has dirty or unfiltered liquid. Sediments and other particles can accumulate in the tank’s bottom, taking an extended time to flush out.

Still, draining the water heater cannot be more straightforward than this.

Read next: Step-by-step guide to remove sediment from water heater

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