Does A Tankless Water Heater Need A Water Softener?

A tankless water heater does not necessarily need a water softener. However, installing a water softener can prevent mineral build-up and extend the lifespan of the heater.

Hard water, which contains high levels of minerals, can lead to scale formation inside the tankless water heater, affecting its efficiency. By using a water softener, you can remove these minerals and reduce the risk of scale build-up, ensuring optimal performance and durability of the unit.

Additionally, softened water also has benefits for other household appliances and plumbing fixtures, as it helps prevent clogging and improves the overall lifespan of your plumbing system.

Does A Tankless Water Heater Need A Water Softener?


What Is A Tankless Water Heater And How Does It Work?

Brief Introduction To Tankless Water Heaters

Tankless water heaters, also known as on-demand water heaters, are becoming increasingly popular in homes and businesses. Unlike traditional water heaters that store and heat a large amount of water in a tank, tankless water heaters provide hot water only on demand.

This means they do not require a storage tank, resulting in space-saving benefits. So, let’s dive deeper into understanding how tankless water heaters work and if they need a water softener.

Explanation Of How Tankless Water Heaters Work

Tankless water heaters work by quickly heating up water as it flows through the unit. Here’s a breakdown of the process:

  • Flow sensor activation: When hot water is turned on, a flow sensor detects the movement of water and activates the tankless water heater.
  • Heat exchanger: The heat exchanger, powered by either gas burners or electric heating elements, rapidly heats the water to the desired temperature. The heating process is instantaneous and eliminates the need for a storage tank.
  • Continuous hot water: As long as there is a demand for hot water, the tankless water heater continues to heat the water as it flows through the unit. This ensures a constant supply of hot water whenever you need it.
  • Energy efficiency: Tankless water heaters are highly energy-efficient since they don’t have to constantly heat and reheat water in a storage tank. They only operate when hot water is required, resulting in energy savings and lower utility bills.
  • Size considerations: Tankless water heaters are typically more compact than traditional water heaters, saving valuable space in your home or business.

Benefits Of Using Tankless Water Heaters

There are several advantages to using tankless water heaters over traditional ones. Here are a few notable benefits:

  • Endless hot water supply: Tankless water heaters provide an unlimited supply of hot water, ensuring you never run out during showers or while doing laundry.
  • Energy efficiency: By only heating water when needed, tankless water heaters avoid the energy losses associated with storing hot water in a tank. This can lead to significant energy savings over time.
  • Space-saving design: Tankless water heaters are compact and can be mounted on walls or installed in tight spaces, freeing up floor space and offering flexibility in placement.
  • Longevity: Tankless water heaters tend to have a longer lifespan compared to traditional water heaters. With proper maintenance, they can last up to 20 years, whereas storage tank water heaters typically last about 10-15 years.
  • Reduced risk of leaks: Since tankless water heaters don’t store water in a tank, the risk of leaks and water damage is minimized.
  • Improved water quality: Unlike tank-based water heaters, tankless models don’t store water, reducing the chances of water contamination or the buildup of sediment and rust.
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Tankless water heaters offer numerous advantages – from energy efficiency and space-saving design to endless hot water supply and improved durability. While they do not necessarily require a water softener, their benefits can be further enhanced by using one. Understanding the workings of tankless water heaters and their advantages can help you make an informed decision for your hot water needs.

The Impact Of Hard Water On Tankless Water Heaters

Hard water is a common issue that many homeowners face, impacting their appliances and overall water quality. But what about tankless water heaters? Do they need a water softener to combat the effects of hard water? In this section, we’ll explore the impact of hard water on tankless water heaters, the definition of hard water and its characteristics, and the common problems caused by hard water in these systems.

Definition Of Hard Water And Its Characteristics

  • Hard water is water that contains high levels of minerals, primarily calcium and magnesium.
  • These minerals enter the water supply from underground sources and can have a negative impact on various household appliances.
  • The hardness of water is often measured in grains per gallon (gpg) or parts per million (ppm).
  • Water is deemed hard if it contains more than 3.5 gpg or 60 ppm of dissolved minerals.

Explanation Of The Effects Of Hard Water On Tankless Water Heaters

  • Hard water can lead to the formation of limescale inside the tankless water heater. Limescale buildup occurs when the minerals in hard water accumulate on the heating elements.
  • Limescale acts as an insulator, reducing the efficiency of the heater and increasing energy consumption.
  • The lime deposits can also impair the heat exchanger’s performance, leading to reduced water flow and pressure.
  • The continuous exposure to hard water can shorten the lifespan of the tankless water heater, requiring frequent maintenance or even premature replacement.
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Common Problems Caused By Hard Water In Tankless Water Heaters

  • Reduced efficiency: Limescale buildup on the heating elements impedes heat transfer, forcing the tankless water heater to work harder and consume more energy to achieve the desired water temperature.
  • Poor performance: With restricted water flow due to limescale deposits, the tankless water heater may struggle to deliver an adequate supply of hot water, resulting in fluctuating temperatures or reduced water pressure.
  • Increased maintenance: Hard water requires more frequent maintenance to descale the tankless water heater and remove mineral deposits. Neglecting regular maintenance can lead to more serious issues and costly repairs.
  • Decreased lifespan: The accumulation of limescale inside the tankless water heater can significantly shorten its lifespan, requiring premature replacement and incurring additional expenses.

By understanding the impact of hard water on tankless water heaters and the problems it can cause, homeowners can make informed decisions regarding the installation of a water softener to protect their investment and ensure optimal performance.

Do Tankless Water Heaters Require A Water Softener?

Importance Of Water Softening For Tankless Water Heaters

  • Hard water contains high levels of minerals such as calcium and magnesium, which can cause significant problems for tankless water heaters if left untreated.
  • The buildup of mineral deposits, or scale, can clog the pipes, reduce water flow, and decrease the efficiency of your tankless water heater over time.
  • Water softening is crucial for maintaining the performance and longevity of your tankless water heater, as it prevents scale buildup and keeps the system running optimally.

Factors To Consider When Deciding To Use A Water Softener

  • Water hardness: The first step is to determine the level of hardness in your water supply. You can test it with a water hardness test kit or contact your local water utility for information.
  • Manufacturer’s recommendations: Check the tankless water heater manufacturer’s guidelines to see if they recommend using a water softener. Some manufacturers may require the use of a water softener to maintain the warranty.
  • Cost: Installing and maintaining a water softener can be an additional expense. Consider the upfront and ongoing costs before making a decision.
  • Water consumption: If you have a high water consumption or live in an area with extremely hard water, a water softener may be more beneficial to prolong the lifespan of your tankless water heater.

Comparison Of The Benefits Of Using A Water Softener With A Tankless Water Heater

  • Scale prevention: A water softener removes minerals from the water, preventing scale buildup in the tankless water heater. This helps maintain its efficiency and overall performance.
  • Extended lifespan: By reducing scale formation, a water softener can significantly extend the lifespan of your tankless water heater. This saves you money in the long run by minimizing the need for repairs or premature replacement.
  • Improved energy efficiency: A tankless water heater equipped with a water softener operates more efficiently, as it doesn’t have to work as hard to heat the water. This can lead to energy savings and lower utility bills.
  • Enhanced performance: With a water softener, you can enjoy improved water flow, consistent water temperature, and reduced downtime due to maintenance or repairs caused by scale buildup.
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Alternative Solutions To Combat Hard Water Effects In Tankless Water Heaters

  • Descaling procedures: Regularly descaling your tankless water heater can help remove any existing scale buildup. Follow the manufacturer’s instructions or consult a professional to ensure the procedure is done correctly and safely.
  • Water filters: Installing a water filter can help remove some minerals and impurities from the water supply. While not as effective as a water softener, it can provide some protection for your tankless water heater.
  • Regular maintenance: Regardless of whether you use a water softener or other solutions, it is essential to schedule regular maintenance for your tankless water heater. This includes flushing the system and inspecting for any signs of scale buildup.

Remember, water softening is vital for preserving the performance and efficiency of your tankless water heater. Considering the factors mentioned above and exploring alternative solutions can help you make an informed decision for your specific needs.


To sum up, the decision whether a tankless water heater needs a water softener ultimately depends on the specific circumstances and preferences of the homeowner. While tankless water heaters are generally less prone to scale buildup, regions with hard water may still benefit from the addition of a water softener.

The buildup of minerals can lead to decreased appliance efficiency and a shorter lifespan. However, it’s important to consider the potential downsides of water softeners, such as increased sodium levels in the water and the need for ongoing maintenance. Therefore, it’s crucial for homeowners to assess their water quality, consult with professionals, and weigh the pros and cons before making a final decision.

Regardless of the choice made, regular maintenance and monitoring is key to ensure the efficient and long-lasting performance of a tankless water heater.


I am a mechanical engineer and love doing research on different home and outdoor heating options. When I am not working, I love spending time with my family and friends. I also enjoy blogging about my findings and helping others to find the best heating options for their needs.