Water Quality in Round Rock, TX

Round Rock's water has very hard water (195 PPM). A water softener is recommended to protect plumbing and appliances. Read below for a full breakdown.

City of Round Rock · Source: Lake Georgetown · Serves 119,468 residents

195
Hardness (PPM)
382
TDS (PPM)
1.3
Chlorine (mg/L)
4
PFAS (ppt)
2
Lead (ppb)
195 PPM 0 400 Very Hard
CONTAMINANT LEVELS Hardness 195 PPM TDS 382 PPM PFAS 4 ppt Lead 2 ppb Chlorine 1.3 mg/L Nitrate 4 mg/L

Hardness Scale: Where Round Rock Falls

Soft 060120180250400+
Very hard water

Round Rock's Lake Georgetown supply produces hard water from Central Texas Edwards Plateau limestone.

What Round Rock's Water Means for Your Home

Round Rock residents deal with some of the hardest municipal water in the country. At 195 PPM (11.4 grains per gallon), the water contains high concentrations of dissolved calcium and magnesium picked up from the regional geology as surface water is treated and distributed. This is not a safety issue. The minerals are safe to consume. But they create real, measurable costs for homeowners. Hard water at 195 PPM costs the average household $800 to $1,200 per year in hidden expenses, including higher energy bills from scale-insulated water heaters, increased soap and detergent usage, and premature appliance failure. Many Round Rock homeowners discover this only after a water heater replacement or plumber visit.

Beyond hardness, Round Rock's water quality is generally within EPA guidelines for regulated contaminants. Chlorine is present at 1.3 mg/L as a disinfectant residual, which is normal for municipal water systems. If you notice a pool-like taste or experience dry skin, a whole-house carbon filter is the most common and affordable solution. For homeowners who want to understand the full picture, requesting your utility's annual Consumer Confidence Report provides neighborhood-level data.

ContaminantDetectedHealth GuidelineLegal LimitStatus
Hardness (as CaCO₃)195 PPM< 60 PPMNo federal limit⚠ Very Hard
Total Dissolved Solids382 PPM< 300 PPM500 PPM⚠ Elevated
PFAS (total)4 ppt4 ppt (EPA)4 ppt (2024)✓ OK
Lead2 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine1.3 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate4 mg/L5 mg/L10 mg/L✓ OK

Recommendations for Round Rock Homes

🧂 Water Softener
At 195 PPM (11.4 GPG), Round Rock's water is very hard. Scale will accumulate in pipes, water heaters, and on fixtures. A salt-based ion exchange softener removes the calcium and magnesium causing the problem. For a typical Round Rock household of 2 to 4 people, a 48,000-grain softener is the right starting size.
Learn more about this solution →

About Round Rock's Water Supply

Water Utility: City of Round Rock

Water Source: Lake Georgetown

Population Served: 119,468

Hardness: 195 PPM (11.4 grains per gallon)

Water quality can vary by neighborhood and season. The values above represent typical averages reported by City of Round Rock. To get exact numbers for your address, request a copy of the most recent Consumer Confidence Report (CCR) from your utility, or have your water independently tested.

Compare Round Rock to Other Texas Cities

Houston

120 PPM · Hard

San Antonio

240 PPM · Very Hard

Dallas

100 PPM · Moderately Hard

Fort Worth

110 PPM · Moderately Hard

El Paso

265 PPM · Extremely Hard

Arlington

124 PPM · Hard

Frequently Asked Questions About Round Rock Water

Is Round Rock tap water safe to drink?
Round Rock's water meets EPA legal standards for drinking water safety. However, legal limits and health-optimal levels are different things. Review the contaminant table above for specific numbers and how they compare to both legal limits and health guidelines.
Do I need a water softener in Round Rock?
Yes. At 195 PPM (11.4 GPG), Round Rock's water is very hard. Without a softener, expect visible scale buildup on faucets and shower heads, reduced water heater efficiency (15 to 25 percent higher energy costs), spotted dishes and glassware, and soap that does not lather well. A salt-based water softener is the standard solution. For a typical Round Rock home with 2 to 4 residents, a 48,000-grain system is the most common starting size.
What water filter is best for Round Rock?
The best filter depends on which contaminants you want to address. For chlorine taste and odor, an activated carbon filter is effective and affordable, available as under-sink, countertop, or whole-house systems. See our softener vs. filter guide to understand the difference between these categories.
Where does Round Rock's water come from?
Round Rock's drinking water is sourced from Lake Georgetown and treated by City of Round Rock. Round Rock's Lake Georgetown supply produces hard water from Central Texas Edwards Plateau limestone..
What is the hardness of Round Rock water in grains per gallon?
Round Rock's water hardness is 11.4 grains per gallon (GPG), which equals 195 parts per million (PPM). This is classified as very hard. Most water softener manufacturers recommend treatment above 7 GPG. To convert: 1 GPG = 17.1 PPM.
Does Round Rock water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At 11.4 GPG, Round Rock's water exceeds this threshold. Scale buildup inside the heat exchanger reduces efficiency and can void the manufacturer's warranty. A water softener installed upstream of the tankless heater is the standard solution.
Is Round Rock water safe for babies and infants?
Round Rock's water meets all EPA safety standards and is generally considered safe for preparing infant formula. The hardness minerals (calcium and magnesium) are not harmful. If your home has older plumbing, running cold water for 30 seconds before use is a good precaution to flush any lead from pipes.
How much does hard water cost a Round Rock household per year?
At 195 PPM, hard water costs the average Round Rock household an estimated $800 to $1,200 per year in hidden costs. This includes 15 to 25 percent higher water heating bills from scale insulation, 50 to 75 percent more soap and detergent usage, shorter appliance lifespans (water heaters, dishwashers, washing machines), and increased plumbing maintenance. A water softener typically costs $600 to $1,500 installed and $50 to $100 per year in salt, which means most Round Rock households see a return on investment within 1 to 2 years.

Data sources. Water quality data compiled from EPA SDWIS, EWG Tap Water Database, USGS water hardness studies, and the City of Round Rock Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.