Water Quality in Rancho Cucamonga, CA

Rancho Cucamonga's water has very hard water (192 PPM) and PFAS above EPA limits (7 ppt). A water softener is recommended to protect plumbing and appliances. An activated carbon filter can reduce PFAS levels. Read below for a full breakdown.

CVWD · Source: Cucamonga Valley Water District · Serves 177,603 residents

192
Hardness (PPM)
320
TDS (PPM)
1.4
Chlorine (mg/L)
7
PFAS (ppt)
3
Lead (ppb)
192 PPM 0 400 Very Hard
CONTAMINANT LEVELS Hardness 192 PPM TDS 320 PPM PFAS 7 ppt Lead 3 ppb Chlorine 1.4 mg/L Nitrate 4 mg/L

Hardness Scale: Where Rancho Cucamonga Falls

Soft 060120180250400+
Very hard water

Rancho Cucamonga's water is a blend of imported Colorado River water and local sources. At 192 PPM, the hardness causes noticeable scale on fixtures and reduces soap efficiency. PFAS contamination from industrial activity in the region adds to water quality concerns.

What Rancho Cucamonga's Water Means for Your Home

Rancho Cucamonga residents deal with some of the hardest municipal water in the country. At 192 PPM (11.2 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 192 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 Rancho Cucamonga homeowners discover this only after a water heater replacement or plumber visit.

PFAS contamination is a significant concern in Rancho Cucamonga. At 7 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.

ContaminantDetectedHealth GuidelineLegal LimitStatus
Hardness (as CaCO₃)192 PPM< 60 PPMNo federal limit⚠ Very Hard
Total Dissolved Solids320 PPM< 300 PPM500 PPM⚠ Elevated
PFAS (total)7 ppt4 ppt (EPA)4 ppt (2024)⚠ Above limit
Lead3 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine1.4 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate4 mg/L5 mg/L10 mg/L✓ OK

Recommendations for Rancho Cucamonga Homes

🧂 Water Softener
At 192 PPM (11.2 GPG), Rancho Cucamonga'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 Rancho Cucamonga household of 2 to 4 people, a 48,000-grain softener is the right starting size.
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🔬 Activated Carbon Filter for PFAS
PFAS detected at 7 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.
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About Rancho Cucamonga's Water Supply

Water Utility: CVWD

Water Source: Cucamonga Valley Water District

Population Served: 177,603

Hardness: 192 PPM (11.2 grains per gallon)

Water quality can vary by neighborhood and season. The values above represent typical averages reported by CVWD. 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 Rancho Cucamonga to Other California Cities

Los Angeles

180 PPM · Hard

San Diego

200 PPM · Very Hard

San Jose

183 PPM · Very Hard

San Francisco

21 PPM · Slightly Hard

Fresno

126 PPM · Hard

Sacramento

18 PPM · Slightly Hard

Frequently Asked Questions About Rancho Cucamonga Water

Is Rancho Cucamonga tap water safe to drink?
Rancho Cucamonga'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 Rancho Cucamonga?
Yes. At 192 PPM (11.2 GPG), Rancho Cucamonga'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 Rancho Cucamonga home with 2 to 4 residents, a 48,000-grain system is the most common starting size.
What water filter is best for Rancho Cucamonga?
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. 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 Rancho Cucamonga's water come from?
Rancho Cucamonga's drinking water is sourced from Cucamonga Valley Water District and treated by CVWD. Rancho Cucamonga's water is a blend of imported Colorado River water and local sources. At 192 PPM, the hardness causes noticeable scale on fixtures and reduces soap efficiency.
What is the hardness of Rancho Cucamonga water in grains per gallon?
Rancho Cucamonga's water hardness is 11.2 grains per gallon (GPG), which equals 192 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 Rancho Cucamonga water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At 11.2 GPG, Rancho Cucamonga'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 Rancho Cucamonga water safe for babies and infants?
Rancho Cucamonga'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 Rancho Cucamonga household per year?
At 192 PPM, hard water costs the average Rancho Cucamonga 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 Rancho Cucamonga 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 CVWD Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.