Hard Water Problems in Dallas-Fort Worth Homes
Hard water is water carrying dissolved calcium and magnesium. Hardness is not a health concern, according to USGS, but it leaves scale and film behind, and the DFW utilities that publish a hardness figure report water from moderately hard to very hard.
What Causes Hard Water
The U.S. Geological Survey defines water hardness as the amount of dissolved calcium and magnesium in the water. As water moves through soil and rock, USGS explains, it dissolves small amounts of naturally occurring minerals and carries them along to the water supply.
DFW utilities that publish hardness report it in parts per million (ppm) as calcium carbonate. USGS uses milligrams per liter (mg/L), which it treats as generally equivalent to ppm. Water treatment uses grains per gallon, and the Water Quality Association puts one grain per gallon at 17.1 ppm.
| Hardness | ppm (mg/L) | Grains per gallon |
|---|---|---|
| Soft | 0 to 60 | under 3.5 |
| Moderately hard | 61 to 120 | 3.5 to 7.0 |
| Hard | 121 to 180 | 7.0 to 10.5 |
| Very hard | over 180 | over 10.5 |
USGS classes. Grains per gallon converted at WQA's 17.1 ppm per grain; WQA also calls 7.0 to 10.5 gpg hard and anything above 10.5 very hard.
How Hard Is Dallas-Fort Worth Water?
Hardness depends on the water source, so it changes from city to city. These are the numbers DFW utilities publish in their own water quality reports.
Fort Worth and Southlake
108 to 150 ppm · 6 to 9 gpg · Moderately hard to hard
That is Fort Worth Water's reported total hardness, and its report says the water "is usually hard enough to create a coating on the inside of any metal pipes or fixtures." Southlake buys all of its water from Fort Worth and reports the same range.
Grapevine
117 to 135 ppm · about 6.8 to 7.9 gpg · Moderately hard to hard
Grapevine's 2024 report lists 117 ppm from its own plant and 135 ppm in the water it buys from the Trinity River Authority.
Plano (NTMWD Wylie Plant)
96 to 200 ppm · about 5.6 to 11.7 gpg · Moderately hard to very hard
That is the 2025 range at the Wylie plant of the North Texas Municipal Water District, whose member cities include Plano, McKinney, Allen and Frisco. NTMWD describes its water as "moderately hard," primarily due to minerals in Lavon Lake.
Dallas
No published hardness figure
Dallas Water Utilities does not list hardness in its annual water quality report. If you are on Dallas water, a test at the tap is the way to get a number.
Private Wells
No utility report · Test your own well
The Texas Water Development Board describes Trinity Aquifer groundwater as "fresh but very hard" where the aquifer reaches the surface. A test of your own well is the only way to know your number.
Signs of Hard Water
You see hard water in what it leaves behind.
Kitchen
USGS calls hard water one of the most common causes of cloudy dishes and glassware: spots and film on glasses after a dishwasher cycle. Mineral buildup forms inside coffee makers too.
Bathroom
Soap reacts with the calcium in hard water to form soap scum, and your hands can still feel slimy, or coated with a film, after you wash. Scale builds up on faucets and showerheads.
Laundry
USGS notes that hard water takes more soap or detergent to get laundry clean, and that it can shorten the life of fabrics and clothes.
Appliances
When hard water is heated, calcium carbonate drops out as solid deposits. The scale collects inside water heaters and on dishwasher and washing machine surfaces.
What Hard Water Does to Your Home
The cost shows up in plumbing and appliances. EPA notes that homes with significant water hardness may see scale form on fixtures and appliances and find it hard to get soap and detergent to lather. Over time, USGS adds, scale can narrow water pipes and lower water pressure.
The Battelle Memorial Institute measured the effect in a 2009 study funded by the Water Quality Research Foundation, testing 30 water heaters over 90 days. On unsoftened water:
- Gas storage water heaters dropped from 70.4 percent efficiency to 67.4 percent at two years of equivalent service. Battelle projected a life-cycle loss of 8.5 percent at 10 grains per gallon and 12.8 percent at 15.
- Tankless water heaters had to be delimed at 1.6 years of equivalent field service, after their average efficiency fell from 80 percent to 72 percent.
- Low-flow showerheads clogged after an average of 3,203 gallons.
- Dishwashers and washing machines on 26 grain water showed scale on every interior surface after 30 days.
How to Check for Hard Water at Home
Start with your utility's annual water quality report. Look for "total hardness" and divide a ppm figure by 17.1 to get grains per gallon. Then find it in the hardness table under What Causes Hard Water.
A utility range is not your tap, and well water has no report at all.
For an exact number, book a free in-home water test. We measure hardness at your tap, check for other problems at the same time, and give you a straight recommendation with no pressure to buy.
How to Fix Hard Water
For the whole house, a water softener is the system built to remove hardness. Filters and drinking water systems solve other problems.
Water Softener
EPA notes that water softeners can be used to remove excessive hardness. A salt-based softener trades the calcium and magnesium for sodium in a tank of resin beads, so softened water reaches every faucet, shower and appliance in the house.
Why a Carbon Filter or RO Is Not the Fix
EPA lists dissolved minerals among the things activated carbon does not remove, so a carbon filter does not fix hard water. Reverse osmosis treats drinking water at one sink and does not protect your water heater or fixtures.
Hard Water FAQs
Is Fort Worth water hard?
Moderately hard to hard. Fort Worth Water reports 6 to 9 grains per gallon, and the upper end crosses the 7 grain line where the Water Quality Association starts calling water hard.
Is Dallas water hard?
Dallas Water Utilities does not publish a hardness figure in its annual water quality report. The only way to know the hardness at your home is to test the water at your tap.
Is hard water a health concern?
No. USGS calls hardness a property of water that is not a health concern, though it can be a nuisance. The problem is the scale and soap film it leaves behind.
How do I convert ppm to grains per gallon?
Divide the ppm figure by 17.1, the conversion the Water Quality Association uses. For example, 150 ppm is about 8.8 grains per gallon.
Does a carbon filter fix hard water?
No. EPA notes that activated carbon does not remove dissolved minerals, and calcium and magnesium are dissolved minerals. A water softener is the system that removes hardness.
Related Water Problems
Sources
- USGS: Hardness of Water
- Water Quality Association: Glossary of Terms (hardness, grains per gallon)
- USGS: Brackish Groundwater Assessment (mg/L and ppm)
- Fort Worth Water: Water Quality Report
- City of Southlake: Water Quality Report (2025 data)
- City of Grapevine: 2024 Water Quality Report
- NTMWD: 2025 Water Quality Report (Wylie WTP)
- NTMWD: Protecting Our Drinking Water
- Dallas Water Utilities: 2025 Water Quality Report
- Texas Water Development Board: Trinity Aquifer
- EPA WaterSense: Guide to Selecting Home Water Treatment Systems
- Battelle / WQRF: Softened Water Benefits Study, Executive Summary (2009)
Book a Free In-Home Water Test
What happens next
- 1We test your waterIn your home, for hardness, chlorine, iron, and sediment.
- 2We recommend a systemA softener, filtration, reverse osmosis, or a combination. No pressure to buy.
- 3We install itClean, and we walk you through how it works.