How much do plumbers charge to flush a tankless water heater?

Author: Gay Smitham  |  Last update: Tuesday, October 28, 2025

The average cost to flush a tankless water heater can vary. On average, homeowners can expect to spend between $100 and $300 for a professional flush, including any additional maintenance services required. DIY flushing costs can range from $30 to $100, depending on the flushing kit purchased.

How much does a tankless water heater flush cost?

Key Takeaways: Tankless water heater flush cost can range from $50 to $1,300, with an average cost of around $600. The maintenance cost is influenced by factors such as the size of the water heater, materials needing replacement, labor costs, and location.

Do I really need to flush my tankless water heater?

Over time, a tankless water heater may accumulate mineral build up which can erode the walls inside your tank's heating chamber. To properly maintain and clean your tankless water heater, it's important to flush those mineral deposits at least once a year.

How long does a tankless flush take?

On average, this process will take anywhere from an hour to two hours to complete, so make sure you leave yourself enough time to let the cleaning process run its course.

How much does it cost to service a Rinnai tankless water heater?

The cost to service a tankless water heater is $600 on average, but it can cost between $75 and $1,300, depending on the type and scope of the repair. The cost of maintaining your tankless hot water heater can range from as little as $75 and up to $1,300 for more extensive repairs.

How To Flush A Tankless Water Heater The Easy Way | DIY Plumbing

How often should a tankless water heater be serviced?

However, these systems require proper maintenance to prevent premature component failure and ensure long service life. Generally, tankless water heaters should be serviced once a year; however, they may require more frequent maintenance if you have hard water or if you keep your water temperature high.

What is the labor cost to replace a tankless water heater?

Labor is a significant cost factor when installing a tankless water heater. It can add $500 to $3,000 to the cost of the project. Point-of-use models require less work to install, so you'll pay on the lower end for labor.

How do I know if my tankless water heater needs to be flushed?

Common signs it's time to flush or drain your water heater include:
  1. Low water pressure.
  2. Water takes a long time to heat up.
  3. Water isn't the correct temperature or fluctuates.
  4. Noises coming from the tank, such as rumbling or popping.
  5. Sludge or discolored water.
  6. Frequent Repairs.

What happens if you don't descale your tankless water heater?

What happens if I don't flush out my tankless water heater? Mineral deposits may build up. This could cause a clog within the unit and may prevent normal heating activity. Your hot water could also fluctuate and overheat the system, impacting its efficiency.

How long does it take a plumber to install a tankless water heater?

Installing a tankless water heater typically takes four to five hours, depending on the type of system and a household's needs. The installation process duration also depends on your location and which professionals are available when you need an installation.

What happens if you never flush your water heater?

-Reduced Efficiency: As scaling collects at the bottom of the tank, your water heater will become less effective at heating the water in the tank. -Corrosion: If your water heater goes long enough without a proper flush, you could also have corrosion attacking the tank itself, weakening its structural integrity.

What happens if you don't service your tankless water heater?

If you neglect maintenance on your tankless heater, it will reduce the lifespan of your investment. You could go years without performing maintenance and the heater will still function. It won't heat the water efficiently, but it will still produce hot water at a reduced flow rate.

Who descales tankless water heaters?

Plumbing professionals will be able to descale, along with performing any other required tankless water heater maintenance or service. Professionals have all the tools, test equipment, and experience to perform service in less time than most end users.

How much do plumbers charge to flush a water heater?

The national average cost to flush a water heater is $160, but prices can vary in increments based on the tank size. A 30-gallon tank will cost between $90 and $120 on average, while a 70-gallon tank could cost anywhere between $180 and $250.

Can I flush my own tankless water heater?

With the right tools and knowledge, you can certainly flush a tankless water heater by yourself. In fact, there are water heater flushing kits you can buy online for the job, which come with everything you need. They include things like a circulation pump, hoses, a bucket and a cleaning agent.

How much does your electric bill go up with a tankless water heater?

How Much Electricity Does a Tankless Water Heater Use? Many people wonder if tankless water heaters increase electric bills. The answer is no — tankless water heaters can save money on your monthly electric bill because they're 8%-34% more efficient than storage water heaters.

How much does it cost to flush a tankless water heater?

The average cost to flush a tankless water heater can vary. On average, homeowners can expect to spend between $100 and $300 for a professional flush, including any additional maintenance services required. DIY flushing costs can range from $30 to $100, depending on the flushing kit purchased.

Can I use vinegar to flush my tankless water heater?

To remove that calcium before it can block the tubes, and to improve the heating efficiency of the heater, we need to flush the tankless water heaters about once a year with vinegar. Vinegar is a weak acid which will dissolve the calcium.

How often should I flush tankless water heaters?

Just like a tank unit, tankless water heaters need to be flushed once per year. Homeowners with hard water should consider flushing and cleaning the unit even more frequently, perhaps every six to nine months because of the excess amounts of magnesium and calcium found in hard water supplies.

What maintenance do tankless water heaters require?

To maximize your tankless water heater's performance and service life, it's important to regularly clean or replace the water filter, clean the air filter (for gas units), and descale and flush the system.

How often should I flush my tankless water heater if I have a water softener?

If you have hard water, it is important to descale and flush your unit at least once a year. If you have a water softening system, we recommend performing a flush of the system every 3-5 years.

Can you burn out a tankless water heater?

If a heating element begins to ground out, it will stay on all the time and overheat drastically. Not surprisingly, the result will be painfully hot water – and that's just for starters. With time, the heater element will burn itself out completely. Then you'll have no hot water at all until the element is replaced.

Is there an IRS tax credit for a tankless water heater?

The federal tax credit for tankless water heaters can lead to significant savings for homeowners. Eligible tankless gas water heaters must have an ENERGY STAR certification and a UEF of greater than 0.95. Homeowners can claim up to $3,200 in tax credits for eligible home improvements in a single year.

What is the downside of a tankless water heater?

Before you commit to buying a tankless water heater, the primary drawbacks to know include: Higher upfront costs. Tankless water heaters are, on average, quite a bit more expensive to buy and install than tank water heaters. Access to fuel.

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