5 Best Water Heaters for Hard Water Reviews

Hard water may be a pain, reducing the life of your water heater regularly. It not only leaves layers that make water heater maintenance more difficult, but it also can jam the heater, lowering its heating effectiveness. This review definitely helps you to choose the best water heaters for hard water.

Best Water Heaters for Hard Water

It can damage your appliances as well as your taps and pipes in the bathroom and kitchen. As a result, water heaters are now designed to resist hard water. To buy the best water heaters for hard water, every customer should consider these models.

Top-Rated Water Heater for Hard Water

Standard water heaters or systems will not suffice when it comes to hard water, necessitating specialized solutions. In this portion of the post, I’ll tell you about my suggestions for the finest water heaters for hard water or comprehensive systems. Let’s get this party started, shall we?

Here is the Quick Review of Top-Rated Water Heaters for Hard Water



    • Brand: Rinnai
    • Material: Stainless Steel
    • Power: 1500W
    • Best Thing:Heat Water Super Fast
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    • Brand: Rheem
    • Power Source: Corded Electric
    • Power: 2400W
    • Best Thing: Self-modulating
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    • Brand: Rheem
    • Flow Rate: 9.5GPM
    • Power Sources: Corded Electric
    • Best Thing: Best For Small Houses
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Eemax EEM24027

      • Brand: Eemax
      • Material: Stainless Steel
      • Power: 3000W
      • Best Thing:Digital Temperature Display
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Titan SCR2

      • Brand: Titan
      • Material: Stainless Steel
      • Power: 54 Amp
      • Best Thing:Best for Large Family
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5 Best Water Heaters for Hard Water

Let’s discuss in detail the water heater for hard water.

Rheem RTEX-24 

Rheem RTEX-24

Although the RTEX-24 can handle up to three showers running simultaneously, a suitable size is crucial for your location. You will undoubtedly be dissatisfied if you purchase a device that is too tiny.

With the RTEX-24, you’ll have a lot of installation possibilities. This best water heater for hard water does not require venting and can be installed anywhere.

You won’t have to tuck the unit out of sight, thanks to its crisp, clean lines and elegant finish. This is a terrific alternative that, if properly maintained, will last a long time.

  • Temperature ranges from 80 to 140 degrees Fahrenheit.
  • For easy replacement, it’s connected with a brass top.
  • Advanced self-modulation system.
  • Professional installation is recommended. 

Rinnai RUR199iN


The Rinnai RUR is a powerful tankless water heater that runs on gas, and it has all of the features you’d expect from a high-end model, including the capacity to deliver up to 11 GPM of hot water.

It’s hard to disagree with a Rinnai, and the RUR199iN is an excellent choice. Rinnai has earned the reputation of being the best water heater for hard water, with over a century of expertise and one of the best warranties in the market. A Rinnai has a 20-year average service life!

If a part has to be changed, swapping it out for a new one is simple. There’s no need to invest in a completely new heating system. Although expert installation is generally recommended, all tankless water heaters require it. The RUR199iN features various options and does not require costly Category III material, making professional installation simple.

  • Perfect solution without a separate return line.
  • Received the ENERGY STAR certification.
  • It can operate with Control-R.
  • Incorrect installation voids warranty.

Eemax EEM24027


The Eemax EEM24027 tankless water heater is the best water heater for hard water, and it comes highly recommended. This tankless water heater with a water softener can provide adequate water for tiny houses while consuming no electricity.

Furthermore, this tankless water heater incorporates a self-modulating technology that adjusts the energy consumption to demand.

Quality: This tankless water heater is composed of high-quality materials and works with well water. Its small size allows you to save critical storage space.

Performance: This effective filtration system for tankless water heaters has a high water flow rate appropriate for hard water. A tankless water heater is a small unit that is simple to install. On the other hand, please put it in the nearest toilet and under the kitchen sink. It also boasts a high-efficiency rating and self-modulating technology, which allows the user to regulate energy consumption according to need at any moment.

Features: This water heater provides instant, constant, and unlimited hot water with a built-in water softener. The small design of this tankless water heater saves critical storage space.

User Reviews: Customers have given this product a 65 percent – star rating. Overall Rating: 4.2 out of 5.0. This tankless water heater works well in a closet bathroom and under the kitchen sink.

  • Reasonable Rate.
  • Compact Design.
  • Precious Storage space.
  • Only tiny houses are permitted.

Rheem 95DVLN 


This Rheem tankless water heater is incredibly easy to use, and it may be adjusted using a remote control panel that displays any trouble codes. It’s also quieter than most conventional water heaters, which generate a lot of noise while heating water. It saves 94 percent on energy, resulting in cheaper expenses and constant hot water. 

Uniform better, because of the electrical controls that assure even heating, the water temperature remains consistent. The water is tiny enough to be stored in a cupboard, and this best water heater for hard water is more suitable to be placed in locations with hard water because it is tankless. The Rheem is one of the finest water heaters for hard water since it is easy to maintain and performs well.

  • Easy to use.
  • Low price.
  • Save Energy.
  • Not suitable for a small cabin.

Titan SCR2 Water Heater for Hard Water

Titan SCR2

The finest water heaters for hard water are listed below, and they will give you hot water throughout the winter and help you avoid obstruction caused by hard water.

Titan has a tankless water heater for well water that is both cost-effective and dependable. For houses with significant amounts of hardness minerals in their water, the Titan SCR2 is now one of the most trusted water heating devices.

This is the best water heater for hard water is suitable for a small family, but it should also provide enough hot water for moderate families. Its energy efficiency rating of 99.5 percent puts it on pace with leading tankless water heaters, providing you with a good bang for your budget.

The days of scratching your hair because your showerhead or faucet only generated a modest amount of water are long gone. This water heater is simple to install. You should get this device up and operating in under an hour if you have a basic understanding of electrical systems.

The device’s control arrangement is popular due to its simplicity. This tankless water heater includes 10 progressive LED indicator lights that inform you how much water is hot or cold, and you can modify the temperature using the blue down and red up buttons. This is the most straightforward control interface you’ll ever see.

Regrettably, I feel its control panel be uninspiring and archaic. The LED lights are lovely, and there’s no way to tell the tankless heater’s absolute water temperature. I also discovered a few reports of electrical components overheating.

  • Easy to use.
  • Low price.
  • Save Energy.
  • Few reports of component overheating.

Choosing the best water heater for hard water applications is easy if you know what features to identify. We prepared this buying guide to help you navigate the vast collection of water heaters that can serve your needs.

Consider these things before buying a water heater for hard water.

Tankless or With a Tank?

The first thing you have to consider when buying a water heater is the type. Do you need a tankless water heater or a storage tank system? Tankless water heaters provide on-demand hot water, giving you better cost savings and energy savings. Tankless water heaters are also space-savers and are more straightforward to install than water heaters with storage tanks.

If you consume at least 50 gallons of hot water at a time, a storage water heater might be a better choice than tankless water heaters.

Electric or Gas?

In general, natural gas water heaters are more cost-efficient to operate than electric water heaters. You can also use propane gas, in case you want to take your tankless water heater outdoors or in your RV. Unfortunately, you may have to be proficient in making the right connections on both your water line and gas supply line.

Electric tankless water heaters are ideal for households that have lower electric energy bills. These water heaters are also effortless to install, eliminating the need for propane or natural gas supply line connections. Unfortunately, it may be more expensive to operate.

Limescale-reduction or -inhibition Characteristics

Since you are looking for a tank or tankless water heater that works even with hard water, you may have to look for robust features. For example, a tankless water heater might have advanced technology that stops hard water minerals from building up in the water heater’s heat exchanger and heating element parts.

Some tankless water heaters may use a different material for their heat exchanger. For instance, they can use solid copper, which is more resistant to limescale formation than other products. Unfortunately, not many tankless or tank water heater manufacturers publish their limescale-reducing or limescale-inhibiting features in their marketing materials. That is why you may have to dig deeper into the available literature.

Energy Efficiency

You lose energy every time you heat something, including water. Your heat source can be either electricity, propane, or natural gas. These energy sources are not free. That is why you should purchase a water heater that has a high energy efficiency rating. In simple words, you will want to heat your water fast without spending more energy than necessary. You also have to minimize heat loss.

As much as possible, one should choose a tankless or tanked water heater with an energy efficiency score of at least 95%. One may also want to look at the product’s Uniform Energy Factor grade or UEF. Ideally, the higher the UEF score, the better the water heater.

Additional Water Heating Parameters

Three parameters are crucial to any water heater: first-hour rating, recovery rating, and water flow rate. Because tankless water heaters do not have storage tanks, the first two characteristics do not apply. If one chooses a water heater with a storage tank, one will want a product with a high first-hour and recovery rating.

As for the water flow rate, one should always choose a tankless or tanked water heater with a high value if one wants an uninterrupted hot water supply. However, it is essential to recognize that tankless water heaters have a lower water flow rate than tanked water heaters. On average, a tankless water heater should have a water flow rate of at least 2 gallons per minute. Tanked systems can provide as much as 10-20 GPM.

Frequently Asked Questions about the Best Water Heaters for Hard Water

How Does Hard Water Affect Water Heaters?

Hard water contains minerals, primarily magnesium and calcium. These minerals scale the water heater by adhering to its edges. They’re tiny white particles that may be seen with the naked eye. They shorten the life of the tankless water heater once they begin to accumulate on the heater’s wall. It makes no difference whether your heater has a tank or is tankless; both are susceptible to scaling due to hard water. 

On the other hand, tankless water heaters are less susceptible to it, and the following is a list of the most suitable water heaters for hard water. However, there are a few steps by which we can save our water heater from scaling. Other options include keeping the temperature at a safe level, using acid, and employing a filtration system.

What are the most trusted water heater brands for hard water?

Bosch and Stiebel Eltron are two of the most trustworthy water heaters for hard water brands you can buy. Established in 1886, Bosch is a global name in engineering and technology solutions. You can expect its water heaters to be top-notch.

Another German company with almost 100 years of experience in making innovative heating products is Stiebel Eltron. Other noteworthy water heater brands include Rinnai, EcoSmart, Titan, Chronomite, and Gasland.

If you want to use other water heater brands, reading consumer reports can give you a clue as to a brand’s real-world performance.

Is it really necessary to have a hard water system?

The need for a special water system for hard water depends on how “hard” the liquid running through your plumbing system is. For example, the US Geological Survey considers a fluid with no more than 60 mg/L of calcium carbonate “soft.” If the CaCO3 is between 61 and 120 mg/L, you can look at it as “moderately hard.”

Any CaCO3 reading beyond 180 mg/L is “very hard”. The higher the CaCO3 level present in your water, the greater the risk of limescale formation. If you have chalky plaques on your water heaters, they can make them work harder and use more energy than they need to, which can make your electric or gas bill go up.

That is why it is always a good idea to have a water softener or any other technology that can prevent CaCO3 from forming limescale in your plumbing system and water appliances, such as a tanked or tankless water heater.

Can you use a tankless water heater with hard water?

Ideally, no, you should not use hard water with a tankless water heater. Fluids that contain at least 180 mg/L of CaCO3 can form limescale in the pipes and the tankless device’s heat exchanger. Limescale can reduce the tankless hot water heater element’s heating efficiency, requiring more energy to heat your water than usual. It has the potential to raise your electric or gas costs.

If you have to use a gas or electric tankless hot water heater with hard water, our best advice is to look for a hot water heater that has a superior-quality heat exchanger and heating elements. The more durable these components are, the more resistant they are to limescale formation.

Another solution is to place a water softener in your plumbing system before the water goes through the hot water heater. Also, you can put in water conditioners, like an electromagnetic unit or a system that stops scale buildup.

How should they be cleaned and cared for?

The amount of cleaning and caring for your hot water heater depends on the device type. Tankless water heaters are pretty straightforward to care for because there are no storage tanks to worry you. However, it is best to keep the tankless water heater free of dust and dirt. Regular checks by a licensed electrician are also a must.

If you have a gas water heater, you need to check the burners and gas lines to make sure they work properly and safely. A hot water heater with a tank requires periodic flushing and cleaning as frequently as once every three to four months. Sediments and other debris must be removed from the tank in order to keep it working at its best.


After reading this article in its entirety, you should have realized that no two tankless water heaters are the same. Some are more efficient, but they are more expensive. Others are more cost-effective but have fewer features; it’s now up to you to pick which one best meets your demands while staying within your budget. After reading this article, you should have enough knowledge to make an educated choice about tankless water heaters.

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