Water Quality in Rochester, MN

Rochester's water has very hard water (200 PPM) and PFAS above EPA limits (6 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.

Rochester Public Utilities · Source: Groundwater wells · Serves 121,395 residents

200
Hardness (PPM)
353
TDS (PPM)
1.1
Chlorine (mg/L)
6
PFAS (ppt)
3
Lead (ppb)
200 PPM 0 400 Very Hard
CONTAMINANT LEVELS Hardness 200 PPM TDS 353 PPM PFAS 6 ppt Lead 3 ppb Chlorine 1.1 mg/L Nitrate 2 mg/L

Hardness Scale: Where Rochester Falls

Soft 060120180250400+
Very hard waterPFAS above EPA limit

Rochester's deep wells in southeastern Minnesota produce very hard water from Paleozoic limestone and dolomite formations.

What Rochester's Water Means for Your Home

Rochester residents deal with some of the hardest municipal water in the country. At 200 PPM (11.7 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 200 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 Rochester homeowners discover this only after a water heater replacement or plumber visit.

PFAS contamination is a significant concern in Rochester. At 6 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)200 PPM< 60 PPMNo federal limit⚠ Very Hard
Total Dissolved Solids353 PPM< 300 PPM500 PPM⚠ Elevated
PFAS (total)6 ppt4 ppt (EPA)4 ppt (2024)⚠ Above limit
Lead3 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine1.1 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate2 mg/L5 mg/L10 mg/L✓ OK

Recommendations for Rochester Homes

🧂 Water Softener
At 200 PPM (11.7 GPG), Rochester'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 Rochester 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 6 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 Rochester's Water Supply

Water Utility: Rochester Public Utilities

Water Source: Groundwater wells

Population Served: 121,395

Hardness: 200 PPM (11.7 grains per gallon)

Water quality can vary by neighborhood and season. The values above represent typical averages reported by Rochester Public Utilities. 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 Rochester to Other Minnesota Cities

Minneapolis

200 PPM · Very Hard

St. Paul

68 PPM · Moderately Hard

Duluth

21 PPM · Slightly Hard

Bloomington

257 PPM · Extremely Hard

Plymouth

254 PPM · Extremely Hard

Woodbury

271 PPM · Extremely Hard

Frequently Asked Questions About Rochester Water

Is Rochester tap water safe to drink?
Rochester'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 Rochester?
Yes. At 200 PPM (11.7 GPG), Rochester'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 Rochester home with 2 to 4 residents, a 48,000-grain system is the most common starting size.
What water filter is best for Rochester?
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 Rochester's water come from?
Rochester's drinking water is sourced from Groundwater wells and treated by Rochester Public Utilities. Rochester's deep wells in southeastern Minnesota produce very hard water from Paleozoic limestone and dolomite formations..
What is the hardness of Rochester water in grains per gallon?
Rochester's water hardness is 11.7 grains per gallon (GPG), which equals 200 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 Rochester water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At 11.7 GPG, Rochester'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 Rochester water safe for babies and infants?
Rochester'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 Rochester household per year?
At 200 PPM, hard water costs the average Rochester 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 Rochester 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 Rochester Public Utilities Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.