Water Quality in St. Paul, MN

St. Paul's water has PFAS above EPA limits (5 ppt). An activated carbon filter can reduce PFAS levels. Read below for a full breakdown.

St. Paul Regional Water · Source: Mississippi River · Serves 307,193 residents

68
Hardness (PPM)
136
TDS (PPM)
0.6
Chlorine (mg/L)
5
PFAS (ppt)
2
Lead (ppb)
68 PPM 0 400 Moderately Hard
CONTAMINANT LEVELS Hardness 68 PPM TDS 136 PPM PFAS 5 ppt Lead 2 ppb Chlorine 0.6 mg/L Nitrate 2 mg/L

Hardness Scale: Where St. Paul Falls

Soft 060120180250400+
Moderately hard water

St. Paul's water comes from mountain watersheds and is moderately hard at 68 PPM. The quality is generally good with low contamination, though hardness is enough that homes with tankless water heaters may benefit from softening.

What St. Paul's Water Means for Your Home

St. Paul's water is moderately hard at 68 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 St. Paul, focus on contaminant filtration rather than softening.

PFAS contamination is a significant concern in St. Paul. 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.

ContaminantDetectedHealth GuidelineLegal LimitStatus
Hardness (as CaCO₃)68 PPM< 60 PPMNo federal limit✓ OK
Total Dissolved Solids136 PPM< 300 PPM500 PPM✓ OK
PFAS (total)5 ppt4 ppt (EPA)4 ppt (2024)⚠ Above limit
Lead2 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine0.6 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate2 mg/L5 mg/L10 mg/L✓ OK

Recommendations for St. Paul Homes

🔄 Salt-Free Conditioner (Optional)
At 68 PPM, St. Paul'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.
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🔬 Activated Carbon Filter for PFAS
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.
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About St. Paul's Water Supply

Water Utility: St. Paul Regional Water

Water Source: Mississippi River

Population Served: 307,193

Hardness: 68 PPM (4 grains per gallon)

Water quality can vary by neighborhood and season. The values above represent typical averages reported by St. Paul Regional 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.

Compare St. Paul to Other Minnesota Cities

Minneapolis

200 PPM · Very Hard

Duluth

21 PPM · Slightly Hard

Rochester

200 PPM · Very Hard

Bloomington

257 PPM · Extremely Hard

Plymouth

254 PPM · Extremely Hard

Woodbury

271 PPM · Extremely Hard

Frequently Asked Questions About St. Paul Water

Is St. Paul tap water safe to drink?
St. Paul'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 St. Paul?
At 68 PPM, St. Paul'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 St. Paul?
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 St. Paul's water come from?
St. Paul's drinking water is sourced from Mississippi River and treated by St. Paul Regional Water. St. Paul's water comes from mountain watersheds and is moderately hard at 68 PPM.
What is the hardness of St. Paul water in grains per gallon?
St. Paul's water hardness is 4 grains per gallon (GPG), which equals 68 parts per million (PPM). This is classified as moderately hard. To convert: 1 GPG = 17.1 PPM.
Does St. Paul water damage tankless water heaters?
At 4 GPG, St. Paul'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 St. Paul water safe for babies and infants?
St. Paul'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 St. Paul Regional Water Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.