Green Bay's water has hard water (166 PPM) and PFAS above EPA limits (7 ppt). An activated carbon filter can reduce PFAS levels. Read below for a full breakdown.
Green Bay Water · Source: Lake Michigan, Fox River · Serves 107,395 residents
166
Hardness (PPM)
207
TDS (PPM)
0.8
Chlorine (mg/L)
7
PFAS (ppt)
3
Lead (ppb)
Hardness Scale: Where Green Bay Falls
Soft 060120180250400+
Hard water
Green Bay draws from the Great Lakes, the largest freshwater system in the world. At 166 PPM, the water is hard from the basin's limestone geology. In older industrial cities around the Great Lakes, lead from aging service lines is often a more urgent concern than hardness.
What Green Bay's Water Means for Your Home
Green Bay's water is hard at 166 PPM. This level of hardness causes gradual scale accumulation on plumbing fixtures, inside water heaters, and on dishware. While not as aggressive as cities in the 200+ PPM range, homeowners who install a water softener or salt-free conditioner typically notice improved soap lathering, cleaner dishes, and longer appliance lifespans.
PFAS contamination is a significant concern in Green Bay. 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.
Contaminant
Detected
Health Guideline
Legal Limit
Status
Hardness (as CaCO₃)
166 PPM
< 60 PPM
No federal limit
⚠ Hard
Total Dissolved Solids
207 PPM
< 300 PPM
500 PPM
✓ OK
PFAS (total)
7 ppt
4 ppt (EPA)
4 ppt (2024)
⚠ Above limit
Lead
3 ppb
0 ppb (no safe level)
15 ppb (action level)
✓ Low
Chlorine / Chloramine
0.8 mg/L
Taste threshold ~1.0
4.0 mg/L
✓ Normal
Nitrate
1 mg/L
5 mg/L
10 mg/L
✓ OK
Recommendations for Green Bay Homes
💧Water Softener or Conditioner
At 166 PPM, Green Bay's water is hard. You will see gradual scale buildup on fixtures and inside water heaters. A salt-based softener removes hardness completely, while a salt-free conditioner prevents scale without removing the minerals. Your choice depends on whether you want soft-feeling water or just scale prevention.
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.
Water quality can vary by neighborhood and season. The values above represent typical averages reported by Green Bay 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.
Green Bay'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 Green Bay?
It is worth considering. At 166 PPM, Green Bay's water is hard. You will notice gradual scale buildup in pipes and on fixtures over time. A salt-based softener extends appliance life and improves soap efficiency. A salt-free conditioner is a lower-maintenance alternative if you primarily want to prevent scale.
What water filter is best for Green Bay?
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 Green Bay's water come from?
Green Bay's drinking water is sourced from Lake Michigan, Fox River and treated by Green Bay Water. Green Bay draws from the Great Lakes, the largest freshwater system in the world. At 166 PPM, the water is hard from the basin's limestone geology.
What is the hardness of Green Bay water in grains per gallon?
Green Bay's water hardness is 9.7 grains per gallon (GPG), which equals 166 parts per million (PPM). This is classified as hard. To convert: 1 GPG = 17.1 PPM.
Does Green Bay water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At 9.7 GPG, Green Bay'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 Green Bay water safe for babies and infants?
Green Bay'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 Green Bay household per year?
At 166 PPM, hard water costs the average Green Bay 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 Green Bay 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 Green Bay Water Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.