Franklin's water has hard water (161 PPM) and PFAS above EPA limits (5 ppt). An activated carbon filter can reduce PFAS levels. Read below for a full breakdown.
City of Franklin Water Management · Source: Harpeth River · Serves 83,454 residents
161
Hardness (PPM)
205
TDS (PPM)
0.8
Chlorine (mg/L)
5
PFAS (ppt)
3
Lead (ppb)
Hardness Scale: Where Franklin Falls
Soft 060120180250400+
Hard waterPFAS above EPA limit
Franklin's Harpeth River supply is moderately hard from the Nashville Basin limestone geology.
What Franklin's Water Means for Your Home
Franklin's water is hard at 161 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 Franklin. 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.
Contaminant
Detected
Health Guideline
Legal Limit
Status
Hardness (as CaCO₃)
161 PPM
< 60 PPM
No federal limit
⚠ Hard
Total Dissolved Solids
205 PPM
< 300 PPM
500 PPM
✓ OK
PFAS (total)
5 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 Franklin Homes
💧Water Softener or Conditioner
At 161 PPM, Franklin'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 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.
Water quality can vary by neighborhood and season. The values above represent typical averages reported by City of Franklin Water Management. 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.
Franklin'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 Franklin?
It is worth considering. At 161 PPM, Franklin'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 Franklin?
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 Franklin's water come from?
Franklin's drinking water is sourced from Harpeth River and treated by City of Franklin Water Management. Franklin's Harpeth River supply is moderately hard from the Nashville Basin limestone geology..
What is the hardness of Franklin water in grains per gallon?
Franklin's water hardness is 9.4 grains per gallon (GPG), which equals 161 parts per million (PPM). This is classified as hard. To convert: 1 GPG = 17.1 PPM.
Does Franklin water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At 9.4 GPG, Franklin'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 Franklin water safe for babies and infants?
Franklin'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 Franklin household per year?
At 161 PPM, hard water costs the average Franklin 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 Franklin 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 City of Franklin Water Management Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.