How Much Does It Cost to Flush a Water Heater?

Average Cost to Flush a Water Heater 

Cost to Flush a Water Heater by Tank Size

The total cost to flush a water heater can vary depending on the tank size. Naturally, the bigger the tank, the more time the plumber might take to complete the whole flushing process and, thus, the higher the labor costs. 

The flushing process includes letting the hot water cool down (which can take anywhere from one to three hours), draining the tank completely, flushing it with cold water, refilling it, and then testing the hot water afterward to make sure the heater is still operational.

Cost to Flush a Water Heater by Water Heater Type 

There are two main types of water heaters: tank water heaters and tankless water heaters. Each type of heater has its pros and cons. The costs to flush each type of water also vary, with tankless water heaters usually costing more to flush.

Tank-Style Water Heater

Draining a tank water heater costs between $75 and $150 on average. This is the standard water heater you'll find in most homes. The heater, which can be powered by gas or electricity, consists of a large, insulated storage tank that holds hot water until it's needed. Tank or storage water heaters allow several users in the home to draw hot water at once. 

The main downside of tank-style water heaters is that you must continually reheat them to maintain the set water temperature, regardless of whether anyone is using hot water. The heater can therefore lose a lot of energy through this process, known as standby heat loss.

Tankless Water Heater

Flushing a tankless water heater costs between $150 and $250. Tankless water heaters only heat water when you open a hot water faucet rather than having a bulky tank where hot water is stored. When you turn off the hot water faucet, the heater shuts off, ending the energy burn. So, with these tanks, there are no standby energy losses. 

In fact, tankless water heaters can be as much as 50% more energy efficient than conventional tank-style water heaters. Besides energy savings, tankless water heaters take up less space, are less likely to leak, and have a longer life span on average.

On the downside, a tankless water heater costs more to purchase and install than a tank-style water heater. Water heaters repair costs for tankless units also tend to be on the higher side. Furthermore, these water heaters take longer to deliver hot water, and the water temperature can be inconsistent when you turn on several outlets at the same time.

Water Heater Flushing Cost Breakdown

The cost of flushing a water heater includes materials and labor. The cost of materials will vary depending on the type of water heater. Labor costs depend on the type of plumber, tank size, and the time it takes to complete the job.

Materials

The material cost to clean a water heater ranges between $20 and $140, depending on the tank type. For a tank-type water heater, the main materials to budget for are:

• Garden hose: $15–$50

• Bucket: $5–$10

For a tankless water heater, you'll need the following:

• Tankless water heater flush kit (comes with a circulation pump, hose, and bucket): $100–$120

• Cleaner (3 gallons of distilled white vinegar): $3–$6 per gallon

Labor

Plumbers usually charge by the hour for their services. The typical rate is between $45 and $200 per hour, depending on the experience level of the plumber and the work needed. Some plumbers may charge you a flat fee rather than an hourly rate for relatively small jobs.

Where the plumber charges an hourly rate, some might have a minimum charge, usually equivalent to a minimum number of hours, regardless of how small a job is. Ask your plumber if they have a minimum charge and bundle together other small jobs around your home to maximize both your time and money. 

Other Cost Factors for Flushing a Water Heater

In addition to materials and labor, there are other more minor cost factors that affect your project total. 

Tasks the Plumber Performs

The cost of a flushing service by a plumber can also vary based on whether the plumber performs additional tasks on top of flushing. Some extra tasks that could increase the total cost of the service include the following:

• Descaling the tank

• Visually inspecting the heater for leaks, loose connections, or rust and performing the necessary repairs

• Inspecting electrical and heating components and the pressure valve to make sure they’re working correctly

• Replacing the anode rod

Single Visit vs. Regular Maintenance

The cost to flush a water heater can also vary depending on whether it's part of an annual maintenance contract or a one-time visit.

With a maintenance plan, you pay an annual fee (of about $200 or more) or a monthly fee, and in exchange, a pro will perform routine checks on your heater throughout the year at regular intervals. They may perform preventive measures like flushing during these checks.

You'll also get other benefits, including priority service in case your heating system breaks, discounts on repairs, or even completely free repairs, depending on the nature of your plan. While signing up for a maintenance plan might cost more than a one-time visit, the extra benefits could be worth it.

Plumber’s Level of Expertise

The average hourly rate for a plumber can vary depending on the level of expertise. Here are typical rates:

• Apprentice: $45–$90 per hour

• Journey-level: $70–$120 per hour

• Master: $90–$200 per hour

The kind of plumber you hire depends on the nature of the project. If you need a flushing service, an apprentice or even a handyperson near you can handle the task. The average hourly rate for a handyperson is $55 to $75 per hour.

However, if your water heater requires extra checks and repairs, such as replacing blown or damaged electrical components, replacing the pressure relief valve, sealing leaks, and so on, you might need to hire a journeyperson or master plumber whose hourly rates are higher.

DIY Water Heater Flushing vs. Hiring a Plumber

You can easily flush a tank water heater yourself and save on the costs of hiring a plumber. Here’s a simple five-step guide to help you flush a tank-style water heater:

1. Turn off the gas or electricity.

2. Turn off the cold water valve at the top of the hot water tank, and then allow the water to cool down.

3. Connect a garden hose to the drain valve at the bottom of the tank. Run the hose to a place where sediments and water can safely drain, like a basement drain.

4. Turn on a hot water faucet somewhere in the home to generate pressure and force water out of the tank.

5. Turn on the drain valve and let the water run out through the garden hose. 

6. Turn the cold water valve back on once the water has completely drained from the tank, and allow water to run through the heater and out of the drain valve for about 10 minutes—or at least until the water draining out of the hose is clear. To test if the water is clear, fill a bucket, let it sit for roughly 60 seconds undisturbed, and then check. Keep draining and repeat this test until the water is clear.

7. Close the drain valve, remove the hose, and let the tank refill.

The process of flushing a tankless water heater differs from that of flushing a tank-style heater. It requires a few extra tools like a circulation pump to circulate a cleaning fluid (usually distilled white vinegar) throughout the system. Still, you can flush your tankless water heater yourself if you have all the necessary tools and know-how. There are water heater flushing kits you can pick up from a hardware store or buy online for between $100 and $120 that come with the necessary tools and instructions to do the job.

However, if you're uncomfortable working with tools or aren't confident in your ability to flush a water heater, consider hiring a plumber near you. A licensed plumber will have the experience and training to perform the job correctly and safely. For an extra cost, they can conduct additional checks and tests on your water heating system to make sure everything is running smoothly.