Water Quality in Gilbert, AZ

Gilbert's water has very hard water (277 PPM). A water softener is recommended to protect plumbing and appliances. Read below for a full breakdown.

Town of Gilbert · Source: SRP, groundwater · Serves 267,918 residents

277
Hardness (PPM)
484
TDS (PPM)
1.1
Chlorine (mg/L)
4
PFAS (ppt)
1
Lead (ppb)
277 PPM 0 400 Extremely Hard
CONTAMINANT LEVELS Hardness 277 PPM TDS 484 PPM PFAS 4 ppt Lead 1 ppb Chlorine 1.1 mg/L Nitrate 5 mg/L

Hardness Scale: Where Gilbert Falls

Soft 060120180250400+
Very hard waterNitrates

Gilbert's very hard water mirrors the southeast Phoenix metro geology.

What Gilbert's Water Means for Your Home

Gilbert residents deal with some of the hardest municipal water in the country. At 277 PPM (16.2 grains per gallon), the water contains high concentrations of dissolved calcium and magnesium picked up from underground limestone and mineral formations. This is not a safety issue. The minerals are safe to consume. But they create real, measurable costs for homeowners. Hard water at 277 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 Gilbert homeowners discover this only after a water heater replacement or plumber visit.

Beyond hardness, Gilbert's water quality is generally within EPA guidelines for regulated contaminants. Chlorine is present at 1.1 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)277 PPM< 60 PPMNo federal limit⚠ Very Hard
Total Dissolved Solids484 PPM< 300 PPM500 PPM⚠ Elevated
PFAS (total)4 ppt4 ppt (EPA)4 ppt (2024)✓ OK
Lead1 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine1.1 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate5 mg/L5 mg/L10 mg/L✓ OK

Recommendations for Gilbert Homes

🧂 Water Softener
At 277 PPM (16.2 GPG), Gilbert's water is extremely 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 Gilbert household of 2 to 4 people, a 48,000-grain softener is the right starting size.
Learn more about this solution →

About Gilbert's Water Supply

Water Utility: Town of Gilbert

Water Source: SRP, groundwater

Population Served: 267,918

Hardness: 277 PPM (16.2 grains per gallon)

Water quality can vary by neighborhood and season. The values above represent typical averages reported by Town of Gilbert. 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 Gilbert to Other Arizona Cities

Phoenix

220 PPM · Very Hard

Tucson

288 PPM · Extremely Hard

Mesa

300 PPM · Extremely Hard

Chandler

300 PPM · Extremely Hard

Glendale

294 PPM · Extremely Hard

Scottsdale

250 PPM · Extremely Hard

Frequently Asked Questions About Gilbert Water

Is Gilbert tap water safe to drink?
Gilbert'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 Gilbert?
Yes. At 277 PPM (16.2 GPG), Gilbert's water is extremely 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 Gilbert home with 2 to 4 residents, a 48,000-grain system is the most common starting size.
What water filter is best for Gilbert?
The best filter depends on which contaminants you want to address. See our softener vs. filter guide to understand the difference between these categories.
Where does Gilbert's water come from?
Gilbert's drinking water is sourced from SRP, groundwater and treated by Town of Gilbert. Gilbert's very hard water mirrors the southeast Phoenix metro geology..
What is the hardness of Gilbert water in grains per gallon?
Gilbert's water hardness is 16.2 grains per gallon (GPG), which equals 277 parts per million (PPM). This is classified as extremely hard. Most water softener manufacturers recommend treatment above 7 GPG. To convert: 1 GPG = 17.1 PPM.
Does Gilbert water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At 16.2 GPG, Gilbert'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 Gilbert water safe for babies and infants?
Gilbert'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 Gilbert household per year?
At 277 PPM, hard water costs the average Gilbert 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 Gilbert 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 Town of Gilbert Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.