Tankless Water Heaters and Hard Water: The BasicsLet me start off here by explaining, in simple terms, what the two main components of this question are:
- Tankless water heaters: A tankless water heater is exactly what it sounds like—a water heater that heats water without needing to use a storage tank. Basically, when you turn your hot water on in your shower or at your sink, cold water travels through a pipe and enters the unit where a gas burner or electric element then immediately heats it up, giving your home a constant, indefatigable supply of hot water.
- Hard water: Hard water has a higher mineral content than average tap water because it has percolated through deposits of limestone and chalk, materials made up of calcium and magnesium carbonates. It’s not a health risk, but some homeowners find hard water annoying because it can cause buildup on fixtures as well as poor soap or laundry detergent performance. For many years, some of our Northern California communities, such as Davis where Cal lives, have had hard water because their towns draw their supply from groundwater rather than a river, and groundwater is almost always higher in minerals.
Can a Tankless Water Heater Work in a Home With Hard Water?The answer is yes, a tankless water heater can work in a home with hard water, but the combination can be problematic if left unchecked because there’s the possibility of pipe scaling, which is when calcium and magnesium salts, or other minerals, build up in pipes. The sediment can start restricting your hot water and, actually, the higher the temperature of the water rises, the greater the amount of scaling that tends to occur. Now, it should be noted that there are a lot of newer tankless water heaters that zip water through the heating mechanism so fast that it carries any sediment in the water with it, which means pipe scaling doesn’t become a problem. Some tankless water heaters also have sensors that monitor the heating operation and, if too much scaling occurs due to hot water, these sensors will shut the water heater down until the owner schedules professional maintenance. There are also a number of ways to avoid tankless water heater hard water problems right from the get-go, all of which generally require help from an experienced plumber.
How to Successfully Install a Tankless Water Heater When You Have Hard WaterThere are actually several ways to make sure that your tankless water heater works at optimal levels, even if you have hard water. Work closely with a trained and experienced plumber in order to make sure you find the best solution for you and your unique house. Here are a few ways that a trained plumber can help before you begin running hard water through a tankless water heater in your home:
- #1: Install a pre-filter. A pre-filter, otherwise known as a water softener, is a great way to mitigate this issue. Softeners can filter your water and remove the problematic sediment before it even gets to the heater. The great thing about this is that it will remove sediment from your cold water, too, so you can say goodbye to some of the issues associated with hard water, like splotchy glasses and dry skin. I’ve talked in the past about the advantages of why you should add a softener to a tankless heater, but it’s definitely worth reiterating.
- #2: Get a tankless water heater with high pressure. As I mentioned above, if water zips through the tankless heater fast enough, the sediment won’t be able to accrue and cause pipe scaling—no matter how hard it is. A knowledgeable plumber can ensure that the heater you buy will have high enough pressure to handle your home’s hard water.
- #3: Schedule regular chemical cleanings. The third way to ensure your tankless water heater works well with hard water is to schedule regular chemical cleanings with a trained professional.