Dallas Water Hardness: What the City’s Numbers Mean

Yes, Dallas water is hard. That isn’t our sales pitch. It’s the city’s own answer. In a December 1, 2023 memo to the City Council’s Quality of Life committee, Dallas Water Utilities answered the question “Do we have hard water?” with one word, “Yes,” and put Dallas water hardness at 120 to 155 mg/L as calcium carbonate.

Here’s what that number means, where it comes from, and what to do about it in a Dallas home. We’ll also tell you what it doesn’t mean, because hard water gets oversold.

Dallas water hardness, in plain numbers

Hardness is the amount of dissolved calcium and magnesium in your water. Labs report it in milligrams per liter (mg/L). Water softeners are sized in grains per gallon. The standard conversion is 17.1 mg/L to one grain, so the city’s range works out to roughly 7 to 9 grains per gallon.

The U.S. Geological Survey classifies 61 to 120 mg/L as “moderately hard” and 121 to 180 mg/L as “hard.” Dallas sits right on that line at the low end of its range and well into “hard” at the top.

• Dallas range: 120 to 155 mg/L as calcium carbonate (Dallas Water Utilities, December 2023)
• In grains: about 7 to 9 grains per gallon
• USGS rating: moderately hard to hard

Why the number varies across Dallas

Dallas doesn’t draw from one place. The city’s 2025 Water Quality Report lists seven surface water sources: the Elm Fork of the Trinity River and lakes Ray Roberts, Lewisville, Grapevine, Ray Hubbard, Tawakoni and Fork. The same 2023 memo explains that the East Side plant in Sunnyvale treats water from Ray Hubbard, Tawakoni and Fork, while the Elm Fork and Bachman plants treat water from Ray Roberts, Lewisville and Grapevine. According to Dallas Water Utilities, the city uses no well water at all.

The city publishes a single hardness range, not a number per plant or per neighborhood. Different lakes feeding different plants is a reasonable explanation for why there’s a range, but that’s our inference. The city doesn’t break it down. Either way, the only number that matters for sizing a softener is the one at your tap.

Not on Dallas water? Check who supplies you

Several neighboring cities draw on Dallas Water Utilities supply, including Irving, Carrollton, DeSoto and Cedar Hill. Others, like Garland, Mesquite and Richardson, are supplied by the North Texas Municipal Water District, a different source with its own report. Our water lookup by ZIP code tells you which utility serves your address and links to that utility’s report. If you live in the city itself, our Dallas service area page covers the neighborhoods we work in.

What 7 to 9 grains of hardness does in a Dallas house

Hard water isn’t a health problem, and we won’t tell you it is. The 2025 report says Dallas water meets or exceeds all state and federal requirements, and the Texas Commission on Environmental Quality rates the system “Superior,” its highest rating. Hardness is a plumbing and housekeeping problem:

• Fixtures: white crust on faucets, showerheads and shower glass.
• Dishes: spots and film on glasses out of the dishwasher.
• Water heater: scale building up inside the tank, which is where hardness costs real money.
• Soap: shampoo and detergent that don’t lather well.

Scale doesn’t care how new your house is. A new build in Dallas gets the same water as a 1950s bungalow in Oak Cliff.

The other thing in Dallas tap water: chloramine

Hardness is half the story. Dallas Water Utilities disinfects with chloramine, which is chlorine combined with ammonia. The utility says it uses chloramine instead of chlorine alone to reduce disinfection byproducts called trihalomethanes. That’s a sound public-health choice. It also means there’s disinfectant in the water all the way to your faucet. The 2025 report shows an average total chlorine residual of 2.97 ppm in the distribution system, under the 4 ppm limit.

That residual is where the “swimming pool” taste and smell come from. A softener doesn’t touch it, because softening and filtering are two different jobs. Ion exchange resin handles hardness. Activated carbon reduces chlorine and chloramine.

Which system fits Dallas water

For most Dallas homes on city water, the answer is one tank that does both jobs.

Standard Whole-Home Softener + Filtration

The Standard Whole-Home Softener + Filtration pairs 48,000 grains of softening capacity with coconut-shell carbon for chlorine and chloramine, in a single tank. It’s built for most 3 to 4 bedroom homes on city water.

XL and Dual Tank for bigger households

The XL Whole-Home Softener + Filtration is the same hardware with 64,000 grains of capacity, so a larger household goes longer between regenerations. The Dual Tank for city water goes to 96,000 grains and splits softening and carbon into separate tanks, with a carbon tank that backwashes itself clean. It suits large homes, high water use or heavily chlorinated city water.

Prefer no salt?

A salt-free water conditioner keeps hardness minerals from sticking to your pipes and water heater, but it doesn’t remove them. It prevents scale. It doesn’t soften. We’d rather you know that before you buy one.

Drinking and cooking water

Whole-home systems aren’t designed to catch dissolved solids. For the water you drink and cook with, reverse osmosis at the kitchen sink is the tool for that job. Our HW800 AlkaPro tankless reverse osmosis system is certified to NSF/ANSI 58 and fits under the sink without a storage tank. You can see every option on our drinking water systems page.

How we size a softener for your home

We don’t size from square footage. Capacity comes from two things: your measured hardness and how much water your household uses. Call or fill out the form, and we will go through the numbers with you and tell you which of the three softeners fits and why. If the answer is that you don’t need one, we’ll say that too. Shopping around? Here’s how to compare water treatment companies and what to ask each of them. For more on installation, see our page on water softener installation in Dallas.

Dallas water hardness FAQ

Is Dallas water hard?

Yes. Dallas Water Utilities puts it at 120 to 155 mg/L as calcium carbonate, which is about 7 to 9 grains per gallon. The USGS rates that range moderately hard to hard.

Do I need a water softener in Dallas?

Not for safety. Dallas water meets state and federal standards. Most people get one to stop scale on fixtures and inside the water heater. A quick call gets you the right size before you decide.

Will a water softener get rid of the chlorine taste?

Not by itself. Softening resin handles hardness, and carbon handles chlorine and chloramine. Our whole-home systems put both in one tank.