Water heater manufacturers usually recommend their units be flushed out and cleaned once a year. This will remove any build-up of minerals such as calcium, which can restrict the flow of water if left unchecked.
Flushing your water heater is a straightforward task but choosing a flushing kit can be more of a challenge. To help you decide, we have created this list of the best tankless water heater flush kits available today.
We have reviewed these flushing kits based on the quality of their components, price, and versatility.
- First-grade plastic bucket
- Powerful Zoeller floor sucker pump
- Includes a quart of descaler solution
- 350 GPH pump
- Includes eco-friendly descaler
- Can be used on multiple appliances
- Easy-to-connect rubber hose
- Works effectively with white vinegar
- Large 5 gallon bucket
Do You Need a Tankless Water Heater Flush Kit?
Your local water quality directly affects how often you need to flush your heater. It could be anywhere from every six months to annually (1).
Compared to traditional heaters, a tankless water heater is more vulnerable to mineral build-up (calcium and magnesium). In regular tank water heaters, the build-up is usually at the bottom of the tank, which shouldn’t prevent the heater from working properly.
However, in a tankless unit, the build-up forces the unit to work harder. In time, this can damage the heater’s components.
Hiring a professional whenever you need to descale your unit can become very expensive. Flushing kits aren’t cheap either but they will eventually pay for themselves. If you’re a DIY kind of person, a flushing kit will undoubtedly come in handy.
How to Choose a Tankless Water Heater Flush Kit
A good flushing kit typically has two main qualities.
Includes the Necessary Parts
To perform effectively, a hot water heater flush kit needs to include the necessary parts. The best kits will include a fairly large tank or bucket, which could be anywhere between 3 and 5 gallons.
This bucket will hold the water heater cleaning solution. You can buy specialized cleaning solutions or you can use white vinegar.
A submersible pump is another important feature. The pump is submerged in the bucket and helps circulate the cleaning solution throughout the heater. Obtaining these as part of a kit is important because you can be sure the pump will fit the bucket.
The final essential part of a maintenance kit is two long hoses. These should ideally be 5 feet long so you can easily connect the kit to the heater unit.
These parts are designed to help you easily clean the internal parts of the heater. Alternatively, you can use a garden hose, a bucket, and a separate pump. However, this could make the job more complicated as you will need to make sure everything fits properly.
Works on All Types of Units
Another major benefit of the best flush kits is that they are universal kits and can be used on all heater models. Buying a kit and discovering that it won’t work on your unit can be frustrating and a waste of money!
Like conventional tank water heaters, a tankless heater can be powered by gas or electricity. A good kit will be able to work on both of these.
The Best Tankless Water Heater Flush Kits of 2022
Here are 3 excellent tankless flush kits to consider.
1. My PlumbingStuff Tankless Water Heater Flushing Kit
Best Pump
If you’re new to flushing your tankless water heater, this kit can make the job easier. It includes everything you need to quickly set the kit up and start flushing any heater from major manufacturers such as Rinnai.
The kit comes with a 5-gallon first-grade plastic bucket. It also features two 5-foot hoses which can be easily connected to the valves. The hoses have specialized “ports” which allow you to connect them to pipes without disconnecting the unit.
The pump is a Zoeller floor sucker pump, which is very strong and durable. It can be used fully or even partially submerged. You will also receive instructions and technical details.
The kit includes a quart of Flow-Aide System Descaler. The descaler is a strong, environmentally-friendly solution that quickly breaks down any build-up in the unit.
The Pros
Large Bucket
The bucket is the perfect size for the amount of cleaning solution you need. It is also a good size for all types of tankless water heaters. It’s recommended that you use 4 gallons of solution in the bucket.
Strong Pump
The pump is small but powerful and can be used even if it isn’t fully submerged. Many users praised the pump, saying it is top quality.
Hoses Can Be Easily Attached
The hoses are strong and durable with a steel outer casing. Customers were very pleased with how easily they were attached.
Kit Includes a Descaling Solution
You receive a quart (32 ounces) of Flow-Aide System Descaler. The fluid in this descaling kit is a non-hazardous, biodegradable solution that dissolves scale, rust, mud, and lime.
The Cons
Instructions Could Be More Detailed
Some customers criticized the instructions, saying they were missing some steps. Others said they weren’t detailed enough. Many of these customers instead used online instructional videos or other guides.
Additional Specs
| Weight | 14.5 pounds |
| Hose length | 5 feet |
| Size | Full size |
| Bucket capacity | 5 gallons |
2. J.C Whitlam Flow-Aide Descaler Kit
Best Kit for Multiple Uses
If you want a flushing kit for more than your tankless water heater, this is it. The kit includes two rubber hoses, a pump, a 3.5-gallon bucket, and a Flow-Aide System Descaler.
The bucket isn’t as large as we would like, but it still does its job. The descaler is very strong but environmentally friendly; you won’t need to use much of it.
The kit includes a 350 GPH (gallons per hour) pump, so you can imagine how quickly it will get the job done. It is a rather small pump, but it fits perfectly into the small bucket.
You can also use the kit with other appliances, such as heat exchangers, vacuum pumps, and ice machines. It quickly dissolves and removes lime, scale, rust, and other types of build-up, keeping appliances running smoothly and helping you save energy.
The Pros
The Kit Includes a Descaler
The kit includes 32 ounces of the Flow-Aide System Descaler. It quickly removes any build-up within your unit and is non-toxic and eco-friendly.
Strong Pump
The 350 GPH pump is small but mighty. It will quickly move your cleaning solution from the bucket and through the unit. Customers were very pleased with the pump quality.
Can Be Used on Several Appliances
If you have multiple appliances that require flushing or cleaning, this is an even better investment. You won’t need to purchase separate kits, pumps, or hoses to perform the same task on a different appliance.
The Cons
Hoses Aren’t as Durable as Expected
The hoses are made of rubber and aren’t as durable as we would like. Some customers complained of them leaking. Others users said they only leaked if they weren’t attached properly.
Additional Specs
| Weight | 8.6 pounds |
| Hose length | 5 feet |
| Size | 15 x 10 x 15 inches |
| Bucket capacity | 3.5 gallons |
3. Rheem Tankless Water Heater Flush Kit
Easiest Setup
If you’re looking for a kit that is easy to set up, this might be ideal. The kit includes easy-to-follow instructions to help you get started.
You also receive a pump, two hoses, and a bucket. The bucket will hold 5 gallons, perfect for any cleaning solution you use. Some customers revealed that they only used about 2 gallons of white vinegar, and some even reused it later.
The hoses are made of rubber but they connect easily to the isolation valves of the tankless heater. Some customers weren’t very happy with the rubber hoses, which they felt resembled washing machine hoses.
The pump will circulate 7 gallons per minute through the heater to eliminate the scale and lime. This kit is compatible with all types of tankless water heaters. It could even help to prolong the life of your heater.
The Pros
Easy Instructions
Customers praised the kit for its detailed and easy-to-read instructions. While most kits include a guide, they sometimes skip a step. That won’t be a problem with this one.
Connects Easily
You can start the flushing quickly as the hoses connect easily to the valves. Customers said they were surprised at how quickly they got started.
Large Bucket
The bucket holds 5 gallons, which is great for cleaning as it is a good amount of solution. Customers have said they used about 4 gallons of white vinegar and ran the pump for about an hour.
No Need For Specialized Solutions
This kit was designed for white vinegar only and it does a great job. This means you can save money by not purchasing a specialized cleaning solution. White vinegar is an inexpensive staple in many homes thanks to its versatility.
The Cons
Rubber Hoses Could Be a Problem
Some reviewers complained about the quality of the hoses. They didn’t leak but customers felt they were overpriced.
Additional Specs
| Weight | 13.35 pounds |
| Hose length | N/A |
| Size | 15.4 x 12.7 x 12.4 inches |
| Bucket capacity | 5 gallons |
| Product | Award | Weight | Hose length | Size | Bucket capacity |
|---|---|---|---|---|---|
| My Plumbingstuff Flush Kit | Best Pump | 14.5 lbs | 5′ | Full size | 5 gal |
| J.C Whitlam Flush Kit | Best For Multiple Uses | 8.6 lbs | 5′ | 15″ x 10″ x 15″ | 3.5 gal |
| Rheem Tankless Flush Kit | Easiest Setup | 13.35 lbs | N/A | 15.4″ x 12.7″ x 12.4″ | 5 gal |
FAQs
What Happens if You Don’t Flush Your Tankless Water Heater?
Depending on the quality of your water supply, failing to flush your tankless water heater can cause a gradual buildup of mineral deposits in the heater’s pipes. In time, this inhibits the movement of water through the unit and reduces its efficiency. It can even cause damage to the heater as it is forced to work harder to compensate.
What Size Pump do You Need to Flush Your Tankless Water Heater?
Each of the kits in our list includes a pump that will be suitable for flushing your tankless water heater. The size of the pump is less important than how powerful it is. Generally, pumps designed for this purpose possess about 1/6 horsepower; anything more powerful is unnecessary.
How Much Does it Cost to Flush a Tankless Water Heater?
You should expect to pay about $150 for a water heater flush kit, which will include everything you need to flush the unit. Once you own the kit, future flushes will only require some additional fluid; you can reuse the pump for as long as it continues to work.
