Maricopa's water has very hard water (291 PPM) and PFAS above EPA limits (5 ppt) and elevated nitrates (6 mg/L). A water softener is recommended to protect plumbing and appliances. An activated carbon filter can reduce PFAS levels. Read below for a full breakdown.
Global Water · Source: Groundwater · Serves 58,802 residents
291
Hardness (PPM)
532
TDS (PPM)
1
Chlorine (mg/L)
5
PFAS (ppt)
2
Lead (ppb)
Hardness Scale: Where Maricopa Falls
Soft 060120180250400+
Extremely hard waterPFAS above EPA limitElevated nitrate
Maricopa's groundwater is extremely hard due to caliche and limestone deposits in the Sonoran Desert basin.
What Maricopa's Water Means for Your Home
Maricopa residents deal with some of the hardest municipal water in the country. At 291 PPM (17 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 291 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 Maricopa homeowners discover this only after a water heater replacement or plumber visit.
PFAS contamination is a significant concern in Maricopa. At 5 parts per trillion, levels exceed the EPA's 2024 maximum contaminant level of 4 ppt. PFAS are synthetic chemicals that do not break down in the environment or the human body, which is why they are called "forever chemicals." Long-term exposure has been associated with increased cancer risk, thyroid disruption, and immune system effects. A whole-house activated carbon filter or point-of-use reverse osmosis system can reduce PFAS to safe levels. Look for NSF P473 certification when comparing products.
Contaminant
Detected
Health Guideline
Legal Limit
Status
Hardness (as CaCO₃)
291 PPM
< 60 PPM
No federal limit
⚠ Very Hard
Total Dissolved Solids
532 PPM
< 300 PPM
500 PPM
⚠ Exceeds
PFAS (total)
5 ppt
4 ppt (EPA)
4 ppt (2024)
⚠ Above limit
Lead
2 ppb
0 ppb (no safe level)
15 ppb (action level)
✓ Low
Chlorine / Chloramine
1 mg/L
Taste threshold ~1.0
4.0 mg/L
✓ Normal
Nitrate
6 mg/L
5 mg/L
10 mg/L
⚠ Elevated
Recommendations for Maricopa Homes
🧂Water Softener
At 291 PPM (17 GPG), Maricopa'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 Maricopa household of 2 to 4 people, a 48,000-grain softener is the right starting size.
PFAS detected at 5 ppt, above the EPA maximum contaminant level of 4 ppt. PFAS are linked to cancer, thyroid disease, and immune system effects with long-term exposure. A whole-house granular activated carbon (GAC) filter or a point-of-use reverse osmosis system can reduce PFAS. Look for NSF P473 certification, which specifically tests for PFAS removal.
Nitrate measured at 6 mg/L, above the health guideline of 5 mg/L. Nitrate is especially dangerous for infants under 6 months (blue baby syndrome). A point-of-use reverse osmosis system under your kitchen sink is the most effective nitrate removal method for drinking and cooking water.
Water quality can vary by neighborhood and season. The values above represent typical averages reported by Global Water. 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.
Maricopa's water meets EPA legal standards for drinking water safety. However, legal limits and health-optimal levels are different things. PFAS levels exceed the 2024 EPA health standard, which is a concern for long-term exposure. 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 Maricopa?
Yes. At 291 PPM (17 GPG), Maricopa'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 Maricopa home with 2 to 4 residents, a 48,000-grain system is the most common starting size.
What water filter is best for Maricopa?
The best filter depends on which contaminants you want to address. For PFAS, look for a filter with NSF P473 certification. Granular activated carbon (GAC) and reverse osmosis systems are both effective. Standard carbon pitcher filters may not remove PFAS adequately. See our softener vs. filter guide to understand the difference between these categories.
Where does Maricopa's water come from?
Maricopa's drinking water is sourced from Groundwater and treated by Global Water. Maricopa's groundwater is extremely hard due to caliche and limestone deposits in the Sonoran Desert basin..
What is the hardness of Maricopa water in grains per gallon?
Maricopa's water hardness is 17 grains per gallon (GPG), which equals 291 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 Maricopa water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At 17 GPG, Maricopa'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 Maricopa water safe for babies and infants?
Caution is warranted. Nitrate levels in Maricopa are 6 mg/L, which is above the health guideline of 5 mg/L. Nitrate can cause methemoglobinemia (blue baby syndrome) in infants under 6 months. If you have an infant, use a reverse osmosis filter or bottled water for formula preparation until nitrate levels are confirmed below 5 mg/L.
How much does hard water cost a Maricopa household per year?
At 291 PPM, hard water costs the average Maricopa 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 Maricopa 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 Global Water Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.