Does Fort Worth's Hard Water Damage Tankless Water Heaters?

Search this question and you'll find confident numbers about Fort Worth's water hardness. Look at a few of those pages, though, and the numbers don't agree with each other. Most of them are attached to something for sale.

Here's the part that's actually true. Hard water by itself doesn't damage a tankless water heater. Scale does, and that's a difference worth understanding before you buy one.

Scale is what forms when minerals in heated water settle onto hot surfaces. In a tankless unit, those surfaces sit inside a heat exchanger with narrow passages. That's why tankless heaters need descaling on a schedule, and why skipping it is what actually shortens their life.

Below, you'll see what scale does inside a tankless heater and why these units are more sensitive to it. Then you'll learn how to find your home's real hardness number instead of trusting a sales page. We're Fort Worth neighbors with five decades of expertise.

Hard water itself doesn't. Scale does, and tankless heaters are more sensitive to it because their heat exchangers use narrow passages.

• What happens: Minerals come out of solution when water is heated and build up inside the heat exchanger.
• What it causes: Reduced flow, longer heating, and eventually error codes or shutdowns.
• What prevents it: Descaling on the manufacturer's schedule, plus water treatment if your hardness is high.

Check your own water first. Your utility publishes an annual water quality report with your hardness level, which beats any number you'll find on a sales page. Thinking about tankless? Learn about our tankless water heater installation in Fort Worth.

Water hardness is a measure of dissolved calcium and magnesium. Those minerals come from rock and soil the water passed through before it reached you. They're in the water everywhere, in different amounts.

While they stay dissolved, they don't hurt anything. Heat changes that. When water gets hot, some of those minerals come out of solution and settle onto the hottest surfaces they touch.

That deposit is scale. It's the chalky white crust you've seen on a showerhead or inside a kettle. In a water heater, it forms in the same way, just where you can't see it.

Worth knowing: the EPA doesn't set a legal limit for hardness. Calcium and magnesium aren't harmful to drink. Hardness is a plumbing and appliance issue, not a health one.

A tank heater holds a large volume of water and heats it slowly. Scale collects on the bottom and on the elements, and there's room for it before anything changes.

A tankless heater works differently. Water moves through a heat exchanger with narrow passages and gets heated quickly as it passes. Narrow passages and high heat are exactly the conditions scale likes.

That's why the same water affects a tankless unit sooner. There's less room for buildup before you notice reduced flow or longer waits for hot water.

Here's the part the scare articles leave out. A tankless heat exchanger can be descaled and returned to service. A tank that has scaled up inside can't be cleaned out the same way. Sensitivity isn't fragility. It's a maintenance requirement, and it's one you can plan for.

Before you decide anything, find out what your water actually measures. That number should come from your utility, not from a page selling you something.

Read your water quality report. Every water supplier has to send customers an annual report on what's in their water. It's sometimes called a consumer confidence report. The USGS explains what hardness means and points to those reports as the place to find your levels.

Know the scale. The USGS classifies water by milligrams per liter of calcium carbonate. Soft is up to 60, moderately hard runs to 120, hard runs to 180, and anything above that is very hard.

Or test it yourself. A home hardness test kit gives you an answer the same day, from your own tap.

One caution worth stating plainly. Hardness figures on pages selling water treatment often disagree with each other, sometimes wildly, even for the same city. Your utility's report and your own test are better sources than any of them.

Scale is predictable, which means it's preventable. Every tankless manufacturer builds maintenance into their instructions for exactly this reason.

Descaling. A descaling solution gets circulated through the heat exchanger to dissolve buildup before it becomes a problem. Your manufacturer sets the interval, and harder water usually means doing it more often.

Filters and screens. Tankless units have inlet screens and filters that need cleaning on their own schedule. They're easy to overlook and quick to service.

Records. Keep a log of every service, with dates. Warranties often require documented maintenance, and a paper trail is what proves you did it.

Ask about all three when your unit is installed. Knowing your descaling interval on day one is far easier than working it out after the first error code.