Water Quality in Flagstaff, AZ

Flagstaff's water quality is good overall. Hardness is low at 70 PPM, and no contaminants exceed health guidelines. Most homes here do not need a water softener.

City of Flagstaff · Source: Upper Lake Mary, groundwater · Serves 73,964 residents

70
Hardness (PPM)
165
TDS (PPM)
0.6
Chlorine (mg/L)
3
PFAS (ppt)
2
Lead (ppb)
70 PPM 0 400 Moderately Hard
CONTAMINANT LEVELS Hardness 70 PPM TDS 165 PPM PFAS 3 ppt Lead 2 ppb Chlorine 0.6 mg/L Nitrate 1 mg/L

Hardness Scale: Where Flagstaff Falls

Soft 060120180250400+
Moderately hard water

Flagstaff's water comes from mountain watersheds and is moderately hard at 70 PPM. The quality is generally good with low contamination, though hardness is enough that homes with tankless water heaters may benefit from softening.

What Flagstaff's Water Means for Your Home

Flagstaff's water is moderately hard at 70 PPM. At this level, hard water is not a significant concern for most households. Scale buildup is minimal, and a water softener would provide little measurable benefit. If you are considering water treatment in Flagstaff, focus on contaminant filtration rather than softening.

Beyond hardness, Flagstaff's water quality is generally within EPA guidelines for regulated contaminants. Chlorine is present at 0.6 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)70 PPM< 60 PPMNo federal limit✓ OK
Total Dissolved Solids165 PPM< 300 PPM500 PPM✓ OK
PFAS (total)3 ppt4 ppt (EPA)4 ppt (2024)✓ OK
Lead2 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine0.6 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate1 mg/L5 mg/L10 mg/L✓ OK

Recommendations for Flagstaff Homes

🔄 Salt-Free Conditioner (Optional)
At 70 PPM, Flagstaff's water is moderately hard. Scale buildup is slow but noticeable over years, especially in tankless water heaters. A salt-free conditioner is a low-maintenance option if you want to extend appliance life.
Learn more about this solution →

About Flagstaff's Water Supply

Water Utility: City of Flagstaff

Water Source: Upper Lake Mary, groundwater

Population Served: 73,964

Hardness: 70 PPM (4.1 grains per gallon)

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

Phoenix

220 PPM · Very Hard

Tucson

288 PPM · Extremely Hard

Mesa

300 PPM · Extremely Hard

Chandler

300 PPM · Extremely Hard

Gilbert

277 PPM · Extremely Hard

Glendale

294 PPM · Extremely Hard

Frequently Asked Questions About Flagstaff Water

Is Flagstaff tap water safe to drink?
Flagstaff'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 Flagstaff?
At 70 PPM, Flagstaff's water is moderately hard. Some homeowners at this level do not notice problems, while others see spotting on glassware, film on shower doors, or reduced soap lathering. Homes with tankless water heaters at this hardness level should strongly consider at least a salt-free conditioner, as scale buildup inside the heat exchanger can void the warranty. For other homes, it depends on your sensitivity and fixtures.
What water filter is best for Flagstaff?
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 Flagstaff's water come from?
Flagstaff's drinking water is sourced from Upper Lake Mary, groundwater and treated by City of Flagstaff. Flagstaff's water comes from mountain watersheds and is moderately hard at 70 PPM. The quality is generally good with low contamination, though hardness is enough that homes with tankless water heaters may benefit from softening.
What is the hardness of Flagstaff water in grains per gallon?
Flagstaff's water hardness is 4.1 grains per gallon (GPG), which equals 70 parts per million (PPM). This is classified as moderately hard. To convert: 1 GPG = 17.1 PPM.
Does Flagstaff water damage tankless water heaters?
At 4.1 GPG, Flagstaff's water is unlikely to cause significant issues for tankless water heaters. However, if you notice reduced flow or efficiency over time, scale buildup could be a factor. Annual flushing with vinegar is good maintenance regardless of hardness.
Is Flagstaff water safe for babies and infants?
Flagstaff'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.

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