Nicolette Forbes

By: Nicolette Forbes on July 1st, 2022

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Will Tankless Water Heaters Work with Hard Water?

If you live in the Los Angeles area, you are probably familiar with hard water. While hard water is virtually harmless to you, it is not the best for your plumbing or home appliances, especially your tankless water heater. But can your tankless unit work with hard water? 

In this article, we will:

  • Define what hard water is
  • Discuss how hard water affects your tankless water heater
  • Go through ways to prevent hard water from damaging your tankless water heater

Knowing how hard water affects your tankless water heater is key to getting the most out of your tankless water heater. Monkey Wrench Plumbing is committed to helping you with all your tankless water heater and plumbing needs. Having been in business since 2007, we have worked with thousands of tankless water heaters, and now we are here to give you all of our knowledge so that you, your home, and your tankless water heater are set up for success.


What is Hard Water?

Hard water is water that contains large amounts of minerals like calcium and magnesium. Water hardness is measured on a scale from soft to very hard and is calculated by grains per gallon (gpg) or milligrams per liter (mg/L).

The hardness scale goes like this:

  • Soft: 0-3 gpg
  • Hard: Over 3-7 gpg
  • Very Hard: Over 7-25 gpg

Note: You can test your water’s hardness yourself or with the help of a plumber. See how to do a test here. 


Water hardness test strips

Hard water is safe to drink, and it can even be beneficial for your health. Just think of it as taking a small vitamin. However, like vitamins, it’s not as effective as getting calcium and magnesium through your foods.

Unfortunately, that’s where the hard water benefits stop, as hard water is terrible for:

  • Hair & Skin

When hard water interacts with bar soap, it creates a film called soap scum. This scum makes it hard for you to get completely clean. It can even irritate your skin and cause that squeaking sound when you shower.

  • Clothes

Hard water can also interfere with laundry detergent. It can make your clothes smell sour, look dull, or feel stiff and rough.

  • Appliances & Pipes

Hard water creates scale buildup, also known as white buildup, limestone buildup, or limescale. This buildup can eat through pipes, block up your appliances, create unsightly spots on fixtures and reduce the lifespan of all your appliances, including your water heater.


How Hard Water Affects Your Tankless Water Heater

There are many ways to prolong the lifespan of your tankless water heater like maintenance, for example. But one of the best ways to get the most out of your tankless water heater is to reduce the hard water going into your water heater. 

If you are in an area that has hard water, like much of Los Angeles, it is highly recommended that you get water treatment to prevent early breakdowns. If you have hard water but don't have any kind of water treatment, the hard water going into your tankless water heater will start to build up and can cause your tankless water heater to work harder to heat your water, which can cause a leak in the heat exchanger or early failure of parts inside the unit.

Scale buildup on a fixture

While keeping up with maintenance is important to prolonging the life of your tankless water heater, having water treatment that reduces hard water serves as that extra protection for your tankless water heater. 

Additionally, we have links here that will guide you through what water filtration and hard water are so that you can better understand how hard water affects your tankless water heater and how you can prolong its lifespan through the use of water filtration. Additionally, D-I-Y maintenance tips from our trusted technicians will make it so that you don’t always have to pick up the phone to have a technician come and check your tankless water heater for any old hiccup.

Water Filtration: What is that? Why is it important?

Steps to Flushing Tankless Water Heater

Hard Water: What it does and what it does to your home?


Combating Hard Water

Hard water is a pain in the neck that can affect everything in your home, including your tankless water heater, but it does not have to. There are water filtration systems that will filter out the hard water, which will further help you and your tankless water heater. Some of the water filtration systems to combat hard water include:

  • Whole House Softener

A whole-house water softener will protect your entire home’s plumbing. Softeners will reduce hard water, but they won’t filter out contaminants like chlorine and chloramine. The soft water will help prolong the lifespan of your home’s plumbing appliances and water heater by preventing harmful scale buildup due to hard water.

  • Point-of-Use Filter

Point-of-use water treatment is used for only one area of your home, typically found in a fridge. It can also be used as a pre-filter to protect your tankless water heater. It does not protect any other part of your home from hard water. So if you only have the point-of-use filter on your tankless water heater, it will not protect you from hard water in your shower, kitchen, or bathroom sink. 

  • Flow-Tech

A Flow-Tech is a whole-house water treatment system that sends out a low-frequency signal that is pulsed several thousand times per second and pushed through your entire plumbing system. This electromagnetic signal makes the magnesium and calcium temporarily stick to each other, rather than stick to your pipes and fixtures. While this doesn’t remove hard water minerals from your water, it essentially makes those minerals harmless to your plumbing,


Hard Water, Easy Choice

Your tankless water heater can work with hard water but not for long. Over time, hard water will begin to break down your tankless water heater causing your water heater to work harder, or a leak in the heat exchanger or early failure of parts inside the unit. Even with the proper maintenance, your tankless water heater will not last very long before breakdowns occur without the proper water filtration.

Read the articles below to learn more about the different types of water filtration systems to decide which is best for you and your home, as well as the different kinds of maintenance you can do to get the most out of your tankless water heater.

Water Filtration: What is it? Why is it important?

What type of maintenance does a tankless water heater require?

If you live in the Los Angeles area and would like to have your water tested to see how hard your water is and want to know what options are available for your home, click the “Book” button below. Or if you have any other questions regarding tankless water heaters or about which water filtration option is right for you, you can call us at 310-853-8690, and one of our call center representatives would be happy to help you.