The Best Hot Water Heater for Hard Water

Best Overall
Editors Choice
Bosch Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5) - Eliminate Time for Hot...
EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating...
Rheem 18kW 240V Tankless Electric Water Heater
Bosch Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5) - Eliminate Time for Hot...
EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating...
Rheem 18kW 240V Tankless Electric Water Heater
Best Overall
Bosch Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5) - Eliminate Time for Hot...
Bosch Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5) - Eliminate Time for Hot...
EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating...
EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating...
Editors Choice
Rheem 18kW 240V Tankless Electric Water Heater
Rheem 18kW 240V Tankless Electric Water Heater

Hard water leaves behind limescale deposits on water appliances, including the water heaters, sinks, and dishwashers. The calcium and magnesium minerals present in the hard water affect their performance and lead to eventual breakdown.

If you live in a hard water area, you need to invest in the right water heater as one of poor quality will take you through problems such as blocked water systems and regular replacements.

To avoid such problems, you can invest in one of the best hot water heater for hard water.

Let’s get started on what the market has to offer!

Bosch Tronic 3000 T Electric Mini-Tank Water Heater

Bosch Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5) - Eliminate Time for Hot...
  • CONVENIENT HOT WATER HEATER: 2.5 gallon point-of-use mini-tank fits under your sink to provide...
  • LONG LASTING QUALITY: This electric water heater is easy to maintain and has premium...
  • INDEPENDENT INSTALLATION: 36-37" cord plugs into a 120 volt outlet for independent installation...

Mount this water heater effortlessly, preferably below your sink, as a point-of-use heater to ensure that you can access hot water any time you so wish. You can also opt to tap in the cold water by installing it on your wall or floor.

The high-quality glass lining material makes its maintenance easy as it secures the delicate in-built components.

Avoid the long wait common with poor performing water heaters; the Bosch has a very swift recovery rate with the ability to produce 6.8 GPH. Within seconds you can access hot water on your sink. It can effortlessly serve two sinks, so your family members don’t have to wait in line to access hot water.

Control your water temperature as you wish on this tankless water heater and avoid scalding your hands. The Bosch Tronic 3000 can handle temperatures within the range of 65-145 degrees.

You are assured of a high flow rate; with this water heater with a pressure range of 150 PSI, the heater won’t be reducing your incoming water flow rate.

Invest in this water heater as it’s easily compatible with your already existing plumbing works. The 1/2″ ports make this possible.

Protect your loved ones from the dangers of water heaters that don’t have a relief valve. As a safety measure, this electric tankless water heater has an inbuilt valve that you can use to secure your loved ones.


  • High flow rate
  • In-built relief valve
  • Easy to install
  • Low on maintenance
  • Fast recovery rate
  • Compatible with your existing plumbing works
  • Low energy consumption
  • Has a temperature control knob


  • It’s a bit pricey

Ecosmart ECO 18 Electric Tankless Water Heater

EcoSmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating...
  • The product is highly durable
  • The product is easy to use
  • Manufactured in China

The Ecosmart acts as a point-of-use water heater, and you can choose your favorite position to mount it. It’s an easy-to-operate water heater that will only take up minimal space on your wall. The Ecosmart is beautifully designed and easy to clean.

Save up on your energy costs by investing in this tankless water heater. Its self-modulating technology will save your energy costs by up to 60%.

The copper heating elements that come with Ecosmart make it among the best electric heaters available in the market today. Visually monitor your water temperature that is displayed on the exterior part of this heater. This will enable you to adjust the temperature to your preferred level.

Provide your loved ones with plenty of hot water with the Ecosmart as it can handle high-pressure levels. It has the capacity to produce 2.5 gallons of water per minute. Under warm temperature areas, the Ecosmart water heater can serve multiple outlets simultaneously. Take note, however, for this to work; the incoming water temperature needs to be above 60degrees.

Installation of this tankless water heater takes only a few minutes of your time. Fitted with 3/4″ NPT ports, it’s easy to fix it on your already existing plumbing system. The Ecosmart has a swift record time, and you don’t have to wait for your water to get heated. The water is heated instantaneously, consuming less energy. Cleaning and maintaining this water heater is easy.


  • High efficiency
  • Simple to install
  • Easy to clean
  • Self-modulating technology
  • External temperature display
  • Can handle high incoming pressure
  • Sleek, beautiful design
  • Space efficient
  • Easy to operate


  • Not very durable
  • It’s expensive

Rheem RTEX-18 18kW 240V Electric Tankless Water Heater,

Rheem 18kW 240V Tankless Electric Water Heater
  • External digital thermostatic control with LED display (+/1 degree accuracy)
  • Most advanced self-modulation, adjust power to meet hot water demand
  • Durable Copper immersion two heating elements, field Serviceable. Flow Rate- up to 4.4 GPM

The Rheem is a popular water heater among people living in hard water areas. It has a thermostatic control with an external display that shows you the water heating level to adjust as you wish.

The Rheem is a high-capacity water heater as it has the capacity to fill up to 4.4 gallons per minute. This means you don’t have to worry about the heater reducing your incoming water pressure. It can accommodate impressive pressure levels of up to 150 PSI.

Installing the Rheem performance platinum is simple, and you can do it yourself without incurring extra costs from hiring a professional to assist. Choose an ideal point on your wall to mount it. The threaded 3/4″ ports allow you to fix the water heater easily to your existing plumbing works.

Save your energy costs with this electric water heater as the self-modulation allows you to adjust power needs in your quest for hot water. With the double copper elements, the Rheem is energy efficient and safe to use. Invest in this electric water heater to supply your loved ones with a constant flow of hot water.


  • It has an eternal temperature display for you to monitor
  • Low on maintenance
  • High flow rate
  • Easy to mount
  • Durable
  • High performance
  • Low energy consumption
  • Beautifully designed


  • Does not feature a relief valve
  • It’s a bit costly

Rinnai Indoor Tankless Hot Water Heater / Natural Gas

Rinnai V94iN Natural Gas Tankless Hot Water Heater, 9.8 GPM
  • Endless Hot Water: Enjoy unlimited hot water flow throughout the house; compact, durable, and...
  • Energy and Space Efficient: Space-saving design conserves energy as it heats only when...
  • Optimal Water Pressure: High-performance up to 9.8 GPM hot water flow rate for a powerful,...

Minimize your energy costs by investing in the Rinnai water heater. With an energy efficiency range of 0.82, you are guaranteed this unit will bring down your energy costs. This gas water heater utilizes propane or natural gas in its operations.

Provide your loved ones with a consistent flow of hot water with the gas tankless water heater. With a capacity of 9.8 gallons of water per minute, the Rinnai is a high performer, and it can effortlessly meet the hot water demand of a large family.

You need not worry about the reduced incoming water flow rate; this energy-efficient unit will fit into your pre-existing plumbing works and serve you with hot water as you need it.

Unlike the traditional water heaters that would take up your space, the Rinnai requires minimal space, and you can choose to have it either indoors or outdoors. The Rinnai is among the best gas water heater as it can effortlessly serve multiple hot water points simultaneously.

It is fitted with a recirculation technology that allows the hot water to get to you fast. This means you don’t have to waste time and keep testing whether your water is hot enough. With advancements in technology, the Rinnai gas water heater comes fitted with a Wi-fi monitoring service that makes its maintenance easy. It allows you to mitigate the risk of having the whole system breakdown in good time.

Though the initial cost may be higher, this heater’s durability aspect justifies it in the long run.


  • Long-lasting
  • High flow rate
  • Can provide hot water at different points simultaneously
  • Energy -Efficient
  • Wi-fi enabled
  • Low maintenance requirements
  • Requires minimal space
  • Durable


  • Not very easy to install
  • Among the costly water heaters

Stiebel Eltron Tankless Water Heater

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco,...
  • CONTINUOUS FLOW – Advanced Flow Control patented technology invented by Stiebel Eltron,...
  • SPACE & ENERGY SAVER – Its small, sleek white design saves space yet still provides endless...
  • EASY OPERATION – Electronic switch activates the hot water heater and it’s noise free while...

Treat yourself with this heater and avoid interruptions in your hot water supply. It’s so devastating when taking a shower, then all of a sudden, your hot water turns cold. This electric water heater has an in-built patented technology that helps it retain a constant hot water supply.

Fitted with auto-modulation technology makes this water heater among the best energy-saving heater. Also, the ability to electronically monitor your water flow assists in saving energy.

Anyone in your household can effortlessly operate the Stiebel water heater. The external temperature display makes it possible for you to evaluate the levels you wish. Installing the Stiebel is easy and won’t take up much of your time. Avoid incurring extra plumbing costs. Check out the manual, arm yourself with the right tools and fittings, and you are good to go.

Identify the right point within your home where you wish to install it, and being a tankless electric water heater, this is easy. You can opt to have it as a point of use heater or a whole house, depending on where you choose to install it.

Eliminate the fear of having a reduced flow of your hot water as this heater is fitted with 3/4″ connectors which are the common size of pre-existing plumbing works. This also enables the heater to maintain a high flow level of up to 0.5 gallons of water per minute.


  • Long-lasting
  • Constant hot water temperature
  • Exterior temperature display
  • Displays the history temperature, which allows easy navigation
  • High flow output
  • Easy to install
  • Low on maintenance
  • Suitable copper electric element
  • Requires minimal space


  • Requires regular checks on the flow sensor
  • It’s costly

 Tankless Water Heater Electric ECO TOUCH Point-of-Use Hot Water Heater

Tankless Water Heater Electric 5.5kw 240V, ECOTOUCH Point-of-Use Hot Water Heater Digital...
  • 【INSTANT & SUFFICIENT HOT WATER】Applied with 5.5KW heating system, the electric water...
  • 【SMART SELF ADJUSTMENT】The hot water heater adjusts power input based on flow rate and temp...
  • 【CONVENIENT USE】The tankless water heater comes with digital display & touch control panel...

Upgrade your water heating process and forget the cold water woos that the traditional heaters will subject you to amidst your shower or dishwashing activity. With Eco touch, you don’t have to wait a whole hour for the water to preheat. It’s instantaneous.

Forget the constant interruptions of hot-cold water intervals that some brands subject you to. Get this electric water heater for consistent hot water flows with high-temperature levels of up to 116 degrees. The Eco touch has a high energy efficiency level. It will heat the water to your desired temperature levels and save up to 90% of your energy cost. This is enabled by the heater regulating the power input based on the preset temperature levels in real-time.

It’s a user-friendly water heater as it comes with a digital external display that is touch-sensitive. Therefore setting your preferred temperature level is an easy ordeal. This durable unit will last long, given that the internal electric and water lines are separated, which helps prevent leakage. This also aids in mitigating the risk of limescale build-up that is common in the hard water areas.

Have the Eco touch easily mounted on your favorite spot in your home. Consider having it installed closer to the outlet to save on your power costs. It comes with 1/2″ connectors that make it more compatible with your plumbing system. This also aids in maintaining the high flow level of up to 1.5 GPM.


  • Instantly heats water
  • Consistent temperature levels
  • Easy to clean and maintain
  • Beautiful sleek design
  • Durable
  • High flow rate
  • Energy saving
  • Easy to operate
  • In-built protection features
  • No leakage concerns
  • You get value for money


  • Not very convenient when running multiple points
  • Installation requires extra tools

Camplux ME25 Electric Water Heater 2.5-Gallon with Cord Plug

Camplux ME25 Mini Tank Electric Water Heater 2.5-Gallon with Cord Plug,1.5kW at 120 Volts
  • Saving Energy & Money - Built in insulation foam, reduces heat loss. 2.5-gallon point-of-use...
  • High Quality Built & Elegant Design- Camplux electric water heater has glass-lined tank for...
  • UL Approval Safety - Thermostat Control allows adjustment of water temperature. High Limit...

Save money as you invest in this affordable electric water heater. With a 2.5 tank capacity, the Camplux guarantees a consistent flow of hot water.

It is best utilized as a point-of-use heater to keep you supplied with hot water fast. You can have it effortlessly installed on your wall or the floor close to the outlet you want to access hot water.

Installing it close to the sink will save you the piping costs, and it will also save you on the cost of power.

The Camplux ME25 is a quality unit certified against the UL Approval safety to ensure you are not endangered if it overheats. This feature comes in handy in protecting your household.

It’s easy to clean and maintain the Camplux electric water heater as it’s made of glass. This water heater accommodates high water pressure of up to 150 PSI, which allows you to have hot water consistently in your home. It also has a pressure release valve that acts as a safety measure to protect you from scalding.

The 2.5-gallon tank makes it possible for this water heater to instantly provide you with hot water, even under low-pressure levels. It also reduces the recovery losses as you don’t have to wait long before the water gets to the faucet.

Control the temperature range with the external dial. Heat water to your preferred temperature levels using the dial. The Camplux also features a sleek design that is white in color, making it augur well with your other interior appliances. It’s also a high performer as it can produce 6.8 GPH effortlessly.


  • Features a pressure and temperature relief valve
  • Beautiful sleek design
  • No waiting time
  • High flow
  • Saves on energy
  • UL safety approved
  • Overheating protection
  • Zero noise while functioning
  • Easy to mount
  • Value for money


  • Does not display temperature
  • Lack of display makes it not very user friendly

Ariston Andris 4 Gallon Mini-Tank Electric Water Heater

Ariston Andris 4 Gallon 6 Year 120-Volt Corded Point of Use Mini-Tank Electric Water Heater
  • Compact design; wall or floor mounted (wall bracket included)
  • Provide immediate hot water at the point of use; install as booster or standalone
  • Easy installation; installs right at the point of use with water connection and standard...

This electric water heater has simplified heating water. With the 4-gallon capacity tank, you can instantly access hot water, unlike other brands that you may not access hot water for the first hour.

With the standard voltage of a 120-volt outlet and the 1/2″ ports, you can easily install it yourself without incurring extra electrician or plumbing costs. Save on your space by investing in this sleek design heater. You can choose to have it closest to the outlet faucet where you need the hot water. This will help save on extra piping costs and the waiting time for water to heat.

It also features a relief valve which comes in handy in protecting your loved ones from scalding brought by excess temperatures and pressure levels. Control your desired temperature levels with the external dial knob. With the built-in redundancy, the Ariston water heater eliminates the need for a recirculation, saving you the waiting time.

Get this water heater for your household as it’s a high performer that can hold a pressure level of up to 150PSI, meaning you don’t have to worry about reduced incoming water flow levels. It can also handle temperatures up to 161 degrees, which is quite an impressive rate for a single-point water heater.


  • Quick in heating water
  • Durable
  • Saves on space
  • Relief valve for safety
  • Low on maintenance
  • Easy to mount
  • Value for money
  • Beautiful sleek design
  • Great performance


  • Can’t serve multiple points simultaneously
  • Not UL safety approved

Biselong Electric Hot Water Heater

110V-120V Electric Tank Hot 2.5 Gallon Water Heater Storage,Small Under Sink Counter RV TR 1.5KW...
  • 【SAFE DURABLE & LONGEVITY】Made of stainless steel and never rust,Anti-leakage...
  • 【SMART INVERTER FOR ENERGY SAVING】Automatic heat preservation and storage of hot water, 2.5...
  • 【EASY TO USE】storage tank electric water heater with easy-to-operate knob temperature...

Upgrade your heating water appliance to the Biselong, and you will never regret it. Get hot water instantly and eliminate the long waiting time that is prevalent in conventional water heaters.

Protect your family as this heater is fitted with a safety valve to ensure your loved ones are protected at all times, given that it will automatically drain the excess water caused by excess pressure levels. Buying this water heater is a long-term investment as it’s durable enough given that it’s made of stainless steel and the plastic shell does not rust. It’s also fitted with an anti-leakage plug that prevents leaks which makes it more long-lasting.

The automatic in-built insulation makes the Biselong heater among the best water heater, especially in saving energy. With the smart chip inverter, the heater can retain the preset temperature levels as you use your water.

Biselong water heater is also famed for being user-friendly. You can easily control your water’s warmth to the preferred levels by setting the external knob to the right level. You can even have the Biselong on vacation mode when not in use and also save on energy.

It can also provide hot water for two points simultaneously. Choose to have it fitted in proximity to the points where you need hot water to save your energy and extra plumbing costs. Install the Biselong heater yourself and save money on extra installation costs. Featuring 1/2″ connector ports, the Biselong will easily fit into the already existing plumbing works in your home.

Unlike the conventional water heaters that take up a large space, this water heater takes up minimal space.


  • Requires minimum space
  • Minimum energy required
  • High flow level-2.5GPM
  • Instant hot water access
  • Can serve multiple water usage points
  • Durable
  • Zero leakage
  • Safety valve
  • User friendly


  • It’s pricey
  • It’s not UL safety approved
  • Professional installation recommended

Fouree Perfrct Tankless Water Heater Propane Shower, 2.64GPM

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Invest in this gas and electric heater that works perfectly in hard water areas both indoors and outdoor.

It comes as a whole package, so you don’t have to incur extra costs on accessories like gas valves and regulators.

The Fouree tankless water heater works best for your shower needs; you can use it for your own shower or clean your pets and animals. It comes with a high-pressure shower head that makes it a favorite for most households.

Experience a hot shower anywhere with this high-capacity water heater with the ability to produce 2.6 GPM enough to serve your loved ones with hot water instantly.

This heater is among the best water heater for hard water as it has 6 protection mechanisms to ensure your safety is guaranteed. Most importantly, it’s approved for UL safety measures. It’s an easy-to-maintain water heater, which makes it durable, giving you value for your money.

Install the Fouree yourself and save money on professional installation costs. Choose the most convenient point to mount it on the wall or the floor. It requires minimum space, so you don’t have to worry about large space requirements. The connector fittings that come with it are easily compatible with your existing water line, and you don’t need further modifications.


  • Multiple safety measures
  • Low on maintenance
  • Consistent hot water flow
  • Minimal waiting time
  • User friendly
  • Sustains high-pressure levels
  • Saves energy consumption
  • Minimal space required
  • Withstands high-temperature level
  • Fitted with multiple accessories
  • Portable


  • Can not serve multiple points
  • Its a bit expensive
  • When not properly installed could have leakage problems

Factors to Consider When Buying a Water Heater for Hard Water

1. The Source of Energy

Different water heaters will use varied sources of energy. Some will use electricity, gas, or a combination of both gas and electricity. If you settle for a gas water heater, ensure you have in your home provisions for natural gas or propane gas. The gas water heaters are known to conserve energy more compared to electric heaters.

2. Water Storage

In the market today, there are tank water heaters, and we also have tankless water heaters. Both are effective in functionality. However, the electric tank ones are preferred as they have reduced waiting time. The warmth of the water from the electric tank water is consistent.

3. Space Requirement

Evaluate the space you have to accommodate the water heater. Tankless water heaters take up minimum space and are most convenient for small spaces.

4. Storage Capacity

Check out the amount of water the tank can hold. It is measured in terms of gallons it can hold. Your hot water demands will influence the heater you settle for. If you need hot water at multiple points simultaneously, you may have to go for a larger system.

The tank water heaters’ efficiency is measured by the rate of heating water in the first hour. This should tell you how fast the water in the tank is heated.

5.Hot Water Demand

As you buy a water heater for your household, evaluate whether a whole house heater will serve you better instead of an on-demand point heater. If you need to run hot water on multiple points simultaneously, the whole house is more convenient. Get a single-point heater if you only need hot water at one point.

6. Material Component

Given that you live in a hard water area, ensure the water heater you buy will not hold scale build-up, and it doesn’t rust easily.

7. Safety Precaution

Check out the protection measures that the water heater has taken into account. This is especially important for electric heaters. The elements and thermostats should be made of the right material and the electricity line separated from the waterline. Consider getting a heater that is UL safety approved. This way, you will have peace of mind knowing you are safe using it.

8. Design

Consider getting a water heater that will augur well with your other already existing appliances.

9.Ease of Installation and Maintenance

Get a heater that you can easily install yourself, and it’s easy to maintain. You don’t want a scenario where the heater keeps breaking down, and you have to keep incurring extra repair costs.

Check out the new water heater warranty offered, as it will assure you of its functionality.

10. Flow Rate

Ensure the heater you intend to purchase doesn’t reduce the flow level of your incoming water. Buy a heater compatible with your already existing plumbing works, as this will ensure a consistent hot water supply from your new water heater.

Frequently Asked Questions

1.Which water heater is best for hard water?

The above-mentioned brands work well with hard water. However, you need to flush and clean them constantly to eliminate the scale left by calcium and magnesium deposits in hard water.

2. How long do water heaters last with hard water?

When well maintained, the heaters can last up to 10 years or more. However, in hard water areas, you may consider investing in a water softener for it to get to its maximum life span.

3. Do tankless water heaters work with hard water?

Yes, they work as well as the tank heaters. However, the excess calcium and magnesium minerals reduce its lifespan by a big margin.

4. How do I protect my water heater from hard water?

You could invest in a water softener to remove the minerals responsible for the hardening of your water. This way, your heater will have a long life. Also, ensure the heater is preferably made of stainless steel that does not rust.

The best water heaters will overcome the hard water impurities’ impact from heating and flushing the water.

5. Should I buy an electric or gas water heater as I live in a hard water area?

Gas and electric water heaters work optimally in hard water areas. Consider investing in a whole house water softener to reduce the impact of hard water on the heater.

6. Do I have to do further modification to my plumbing system to accommodate a water heater?

Not really; what you need is to establish your existing plumbing system’s size and ensure the water heater you buy is compatible with it.

7. How much is the best water heater for hard water?

The cost of water heaters varies from one brand to the other. The cost is influenced by several factors including, tank capacity, fuel source, and size. The electric ones cost more compared to the gas ones.


Getting a new water heater for your household is a step in the right direction. It’s a long-term investment that you should get right the first time. To avoid back and forth trips to the store for a water heater, choose one from the ones highlighted above that will serve you well.

Living in a hard water area should not have you worried about missing out on a good water heater. Most of the brands mentioned offer a 12-year warranty on the heaters meaning with proper maintenance, you are assured of a consistent flow of hot water.

Use the buying guide as a checklist when shopping for the best water heater despite living in a hard water area.

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