5 Best Water Softener For Tankless Water Heater

Last Updated on April 24, 2021 by Michael

Did you ever realize that water is classified as hard when there is at least 60mg of magnesium and calcium dissolved in it? Some areas go more than 60 mg and reach 180 mg. It means defeating the water harness is a must. Nowadays, with water softeners, it is not really a tough challenge.


All you need is a cool device to operate as water softeners to effectively work for the tankless water heater. With the right device, you can forget ashy skin, spotty laundry, and stained dishes. On getting the best water softener from the market you are certain to have an easier time with water management.


Why You Need A Water Softener For A Tankless Water Heater

The biggest telltale of hardwater signs is the spotty glassware and dishes. You can easily notice the soap scum film developing on the shower doors, shower walls, or bathtub. It is not easy to remove the film. Your laundry may look dingier as the hard water interferes often with the cleaning agents. There is all possibility that your skin gives a rough and scratchy feel, during the winter months when there is low humidity.


Now that you are here, and are hunting for a water softener for a tankless water heater, you may go through these 5 compiled details. Learn about these water softeners and go through the buyer’s guide to get more clarity.


Best Water Softener for Tankless Water Heater

  • Clearwave CW-125 Softener
  • Aqua-Pure Whole House Scale Inhibition Inline Water System
  • KleenWater Tankless Hot Water Filter System
  • HydroFLOW-Eco-Friendly Alternative to Salt Water Softener
  • Triple Action Poly Salt-Free Water Softener



1. Clearwave CW-125 Softener

best water softener for tankless water heater

check price amazonClearwave CW-125 is an electric softener. The advantage is that it is lightweight and compact weighing around 2.6 pounds. It has 14” length, height 12” and width 4”, that the installation is easy. The design of this softener is such that there is no need for any plumbing. You can directly connect it to the water supply pipe. Clearwave CW-125 reduces the scale build-up significantly without using chemicals or salt.



  • Electromagnetic field changes hard ions structure
  • Connects to the water pipe directly
  • Eco-friendly operation system


Clearwave CW-125 is user-friendly and you can be confident that your water is free from excess salt that is crucial for good health. This water softening system relies on electromagnetic waves.  As the water passes the pipe the hard irons molecular structure changes it. Thus, it does not form limescale in the household appliances or water pipes as they do not carry their adherence power. It is maintenance-free and so you can enjoy saving money. The unit does not ask for frequent plumbing or salt replacements.

  • It is Lightweight
  • Easy to install
  • User-friendly
  • Not suitable for high hard water levels



2. Aqua-Pure Whole-House Scale Inhibition-Inline Water System (Best Budget)

water softener for tankless water heater

check price amazonThe Aqua-Pure Inline Water System is a reliable and versatile system safeguarding the tankless water heater. It blocks the build-up of scale as it has polyphosphates. It expands the hot water appliance’s durability, besides the downstream plumbing fixtures, showerheads, faucets, and pipes. There is an increased flow rate and the pressure is good ranging between 25 to 125PSI, while the range of operating is from 40 to 100F degrees. This system can be installed in the cold water line feeding water heater.



  • It is suitable for tankless and traditional water heaters
  • Has polyphosphates to clear any buildup
  • It allows adjustments proving its versatility to fit in varying sizes of pipes.


The system build is in 304 stainless-steel that is perfect for the current pipes. It ensures to go for a long time as it has corrosion-resistant material. The system ensures the installation as effortless as it has a single cartridge design. However, remember to change it once every six months the disposable filter or even if you notice the flow rate is slow. Adapt the filter to different sizes of pipes, without any issue.

  • Not difficult to install
  • Impressive system build
  • Longer lifespan
  • Some may need installation help



3. KleenWater Tankless Hot Water Filter System

best water softener for tankless water heater reviews

check price amazonKleenWater tankless hot water filter system is a way to safeguard your tankless or traditional hot water systems. It has transparent water filter housing, a bracket, a wrench, and a polyphosphate water filter cartridge, making the food and drinking safe. The phosphate ingredient reacts in the water supply with calcium bicarbonate occurring naturally, which leads to thin, tight, non-corrosive, passivating films appearing on pipe walls. This film separates water from the system of hot water as it functions as a glass coating.


  • It is compatible with tankless and traditional water heater systems.
  • The presence of polyphosphate makes it suitable for drinks and food
  • Suitable for most tankless water heater brands


KleenWater filter is tight offering maximum work pressure and temperature. It is suitable for tankless water heaters and also for cold water applications.  The system is easy to install at any entry point as it ensures anti-scale, anti-corrosion, and sediment filtration for the entire house. In this way, you can keep your plumbing elements and water safe from hard water and corrosive acid water.

  • It is rugged and tough
  • Suitable for tight-budgeters
  • Versatile filter
  • Replacing after a couple of months is mandatory.



4. HydroFLOW-Eco-Friendly Alternative to Salt Water Softener

check price amazonHydroFlow is the right substitute for saltwater softeners. It is eco-friendly and worth a try. It has a system featuring advanced technology that treats electronically the water from blocking the minerals buildup to the pipe, faucet, or water heater. The system does not prevent the white scale, but it prevents the minerals from getting collected into the faucets and pipes.



  • Electronically advanced system
  • Use it for PVC, Copper, PEX, and also galvanized fixtures
  • No minerals assured into the pipes and faucets


HydroFlow water softener requires no plumbing alterations. It is because it is a non-intrusive system. Thus, the installation is a DIY project and allows easy attachment to the cold water line incoming pipe. This system offers a reliable option to fit on pipes that are even less in diameter. It is environmentally friendly and does not make use of any softening chemicals to make the hard water soft. It is also maintenance-free as it is compatible with PVC, PEX, Galvanized, and copper.

  • Easy to install.
  • Maintenance-free, save money.
  • No plumbing alterations required.
  • Not everyone is happy.



5. Triple Action Poly Salt-Free Water Softener

check price amazonTriple Action Poly Salt-Free Water Softener is the right choice for people who do not want to change once every six months a filter. The system is a salt-free water softener that is BPA-free and has NSF certification.  Triple Action Poly salt-free water softener has a compact design and is subtle. On installing it once, you can forget its presence. The wall mount bracket features a rugged build, but do not fear it does not have a bulky look.



  • Includes bacterial filter and two-micron iron filter
  • Useful for city and well water
  • No need for electricity or backwashing


This system as water softener proves its efficiency. It removes intestinal parasites and iron that you can use confidently for city and well water. But, you cannot use it more than 25 grains hard. This water softener is an eco-friendly option and is preferred by many. It is because there is no need to buy cartridges for regular replacements. The system itself comes with a Poly salt-free sifter and a recharge kit.

  • Subtle and compact profile.
  • Eco-friendly option.
  • Comes with a recharge kit.
  • Not the cheapest.
  • Installation may be tricky.



A Guide to Buy Water Softeners

Water softeners mainly remove the magnesium and calcium while it replaces the same with sodium in a mineral tank in association with ion exchange. The water softeners alter the tankless water heater’s life span and you can be free as the soap will not leave any more film anywhere. Knowing the benefits will ensure you cannot stop yourself from buying one for a tankless heater:


  • Spending is cut down– Hard water has high calcium levels and it is a poor heat conductor. Thus the buildup of scale in the hard water from the mineral makes the water heater use extra energy so that you get the required temperature. In this way, the energy bills become higher. It is the minerals present in the water making the water heater work harder to get the heat and consecutively results in paying higher bills.

The water softener blocks the build-up from developing. Thereby, it increases the tankless water heater performance and efficiency.


  • No risk of clogs and plumbing lasts longer– The water heater develops scale build-up and the plumbing also develops it. Thus, the pipe’s diameter becomes smaller and the tubes last less.


The water softener removes the build-up and the messy clogs risk is reduced. Thus you enjoy less time in the bathroom scrubbing, cleaning pipes, sink, the shower, etc.


  • Cleaner laundry and softer skin/hair- Soap fails to lather in hard water, and it means you have to use more to get the desired cleanliness.

Using the water softener system, your clothes are bright and soft. The soap lathers making them clean. Your hair and skin will also thank you for using this water softener. Your skin does not look dull and your hair dry and frizzy. It will look bright and healthy without the presence of magnesium and calcium in the water.


The other buying factors to understand are:

  • The price of the water softener for a tankless water heater varies with the brand, the type of water softener, the materials, the system capacity, and the technology advanced features.
  • You may choose from a saltless water softener and a salt-based softening system. The salt-based are bigger tanks, so buy alternative models, such as electric, magnetic, and chemical-free softening systems.
  • Look for user-friendly features such as a filtration system included so that it will clean the water additionally and make the quality and taste better.
  • The water softener for water heaters must be of high-quality materials ensuring longevity. They should offer a 1-year limited warranty.


If you decide to buy a salt softener ensure the resin capacity. You need to understand your water usage on average considering the family member’s number. If the capacity is larger, the softener does not regenerate frequently. The grain capacity varies and the capacity is associated with the brine tank.


Space is also an important factor to consider when you plan buying water softeners. Most houses may go suitable with a softener of the middle size. It means a 2-piece item with a brine tank and an iron tank is appropriate. These dual-tank systems have a brine tank. Thus, there is a need for a big capacity. You should ask the manufacturer for the dimensions and measurements of the products and go for them. You can get the details online, as well.


One last tip

·         Get all the information before you go shopping. There are water softeners available in many brands and varieties. Every brand claims to eliminate magnesium and calcium, to replace them with sodium ions.


·         Look at the water softeners that are available as salt-free. Check with some professionals as the water softeners come in two types catalytic and electromagnetic to prevent limescale buildup.



Everything comes to an end and it applies to the water softeners for tankless water heater as well. You have the 5 best choices mentioned above and going through the buying guide may ensure you get the information right.  You may stay open to listening to others and check if someone nearby has bought one recently. It will help you to get more details and assistance.


There is no doubt that water softeners are the best for the tankless water heater. Thus, you can enjoy salt-free water and save on unwanted maintenance costs. On the other hand, you have the benefit of wearing bright clothes, showing off your shiny skin and flowy hair!

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