Tankless water heater flush cost in 2024

In this article lets know the real costs of things required to flush a tankless water heater.

Tankless water heaters comes with a lifespan of more than 20 years if the are regularly maintained well. They heat water at high temperatures daily which leads to scales on the surfaces of the heat exchanger. If the water we use has higher hardness these formation of scales becomes faster. If we leave the heater with out flushing or descaling the efficiency becomes low and also leads to damage of few parts.

To avoid this every manufacturer recommends to flush the tankless water heater for at least once in a year. If the water has higher hardness levels it is recommended to flush every in 9 or 6 months. So, in this article we help you in estimating the cost of flushing tankless water heater in 2024. We list all the required items to perform the flush along with their average prices and alternatives if any.

Components required for flushing with costs

1. Submersible pump

submersible pumps to flush tankless water heater

Submersible pump is required to pump the descaling liquid into the pipes and heat exchanger. Generally we use 1/6 HP pump to slowly pump the liquid with out causing harm to fittings. Below we are listing for popular selling 1/6HP submersible pumps in a table along with links and their cost to get average price idea.

16699 Pump$ 44.99
2Superior Pump$ 55.21
3Acquaer Pump$ 59.99
4Green Expert Pump$ 54.99

All the above pumps range between $45 to $60, so we take the average to nearly 50$.

2. Descaling Solution

It is the solution which breaks down the scales by dissolving or loosening from the surfaces of the pipes and heat exchanger. Generally we can use white vinegar as the descaling solution but in the present market there are better solution which perform better than the vinegar. For descaling we need at least 3 gallons of solution so that the pump can easily flush the liquid inside the heater unit. So, we are calculating cost for 3-4 gallons.

Descaling solution of 3-4 gallons
1J.C. Whitlam Flow-Aide(1 Quat)$23.19 =$69.57
2Urnex Dezcal Descaling powder$20.97
3QwikDescaler + (1 Gallon)$28.69
4Calyptus Vinegar 30% dilutes to 6 Gal$24.99

In the above table we listed descaling solutions with prices ranging according to the brands. From them some are concentrated liquids which needs to mixed with specified water to make the solution.

We also listed white vinegar with 30% concentration but tankless water heater manufacturers such as Rinnai recommends using only 5% concentrate vinegar so 1 gallon of 30% makes 6 gallons of 5% vinegar. Always use only 5% concentrated vinegar to flush tankless water heater, if it takes more time, let it be as it wont damage the parts.

We also listed a powder type “Urnex Dezcal Activated Scale Remover” each 7oz pack makes 1 gallon of solution. So we need 3 packs of it to make 3 gallons of descaling solution.

Note: Always clean the heater, submersible pump and other metal parts in contact with descaling solution with water as it is acidic in nature it damages the metal parts if exposed for long times.

3. Bucket

We need a 5 gallon plastic bucket to pour the descaling solution and insert sump pump into it. You can get it in local stores or get it online between 5-8$.

5 gallon bucket on Amazon : @ 7.99$

4. Washing machine or garden Hoses

washing machine hoses

We need two washing machine hoses one from the sump pump to the cool water inlet and another hose from the hot water outlet of heater to the bucket containing solution. We can also get them from local stores near you easily at price of nearly 15$. Choose the hose according to the size of the pump connector.

Washing machine hoses : @ 16.99$

Total cost of flushing

If we calculate the total of the above items we get nearly 105$ which is very less when you compare with a

Sump Pump50$
Descaling solution30$
5 gallon bucket8$
Washing machine Hoses17$
Total cost105$

All the components except descaling solution are reusable so you need not buy them again for your next maintenance schedule. From your next flushing schedule it costs you only the descaling solution which is nearly 30$.

You can get all these items as a single kit online from few companies at nearly same price between 99-150$ which can save you some money and time. Browse through below links to get an idea of the kit.

#Flushing KitLinkPrice
1Superior Brand with descaling powder$ 102.14
2Kelaro Flushing Kit with Flow-Aide Descaler$134.97
2Chromex Brand with descaling liquid$ 134.99
36699 kit without descaling solution$ 89.99
4Green Expert kit without solution$ 94.99


So, if you hire a professional to flush your tankless water heater they charge you between 180 to 350$ for single flush. If you get the required items and do it yourself you can beat it with nearly 100-120$ for the first time and only 30$ from next flush onwards. Always remember don’t use harm chemicals as they can harm your heater.

If you need detailed tutorials on how to perform a maintenance schedule on your tankless water heater, our expert Joseph written step by step guide to make it very clear in the below articles.

We hope you found exactly what you are looking for. If you have any question please comment below.

Joseph Miller

Joseph Miller is a highly experienced water heater repair expert with a passion for keeping homes warm and comfortable. With over 50 years of industry expertise, Joseph has developed a deep understanding of water heater systems and the intricacies of their repair and maintenance.

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