Largest public system
- Gaffney Board of Public Works: TTHM (disinfection byproducts)
- 57 ppb
- Highest running annual average (2025); federal limit 80 ppb.
- Gaffney Board of Public Works, 2025
- Gaffney Board of Public Works: HAA5 (disinfection byproducts)
- 35 ppb
- Highest running annual average (2025); federal limit 60 ppb.
- Gaffney Board of Public Works, 2025
- Gaffney Board of Public Works: Lead (at sampled homes' taps)
- 0 ppb
- 90th percentile of homes sampled (2024); 1 sampled home above the action level. The federal action level is 15 ppb.
- Gaffney Board of Public Works, 2025