01The verdict: is Mill Spring water safe?
Based on EPA testing data, Mill Spring's tap water is generally safe to drink. The water system earned a grade of A+ (95/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 838 residents using surface water (rivers, lakes, or reservoirs).
Nothing over a legal limit
Every contaminant measured in Mill Spring's water is within its EPA limit, and no violations are unresolved.
See the testing ↓Lead is well under the limit
90th-percentile lead is 0.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓1 violation in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Mill Spring's drinking water received a grade of A+ (95 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 838 residents using purchased surface water.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 1 violation on record, including 0 health-based violations. All violations have been resolved.
Mill Spring ranks #8 out of 195 cities in South Carolina for water quality, placing it one of the best in the state. The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection. As a small community water system, Mill Spring may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Mill Spring's water
Every contaminant flagged in Mill Spring, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in South Carolina
Cities ranked by compounds detected Cu Copper in South Carolina
Cities ranked by 90th-percentile copper
03Mill Spring's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 1 violation on record, including 0 health-based violations. All violations have been resolved.
9 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 0 ppb since 2009. Latest reading: 0 ppb (2025) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Mill Spring's water comes from
Mill Spring's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Purchased Surface Water
Rivers, lakes, or reservoirs — more exposed to runoff, agriculture, and seasonal swings than groundwater.
Wholesale supplier
Multi-barrier treatment: coagulation, sedimentation, filtration, and disinfection to meet EPA standards.
1 system
1 water system, operated under local government ownership.
838 people
Residents served across Mill Spring's service area.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards. These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge. The system is operated by local government ownership and serves approximately 838 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| POLK COUNTY WATER SYSTEM | NC1075010 | 838 | Purchased Surface Water |
Water bodies near Mill Spring
As a surface-water system, these water bodies may directly influence Mill Spring's drinking water supply.
05Pressure on Mill Spring's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Flood & storm history
10 federal disaster declarations on record for Spartanburg County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
06How Mill Spring compares
Scores for nearby South Carolina cities on one line, with the average marked.
dashed line = South Carolina average (77/100)
Mill Spring scores 95/100 — above the South Carolina average of 77/100. It outscores 10 of 10 nearby cities. Full South Carolina rankings →
92.1 / 100BCharleston, SC
82.8 / 100FColumbia, SC
37.1 / 100CConway, SC
67.5 / 100BOkatie, SC
83.8 / 100ASpartanburg, SC
91.4 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Mill Spring's water — not generic advice.
A basic carbon filter still helps
Mill Spring's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Mill Spring alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Mill Spring, SC tap water safe to drink?
Mill Spring's water quality earned a grade of A+ (95/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #8 out of 195 cities tested in South Carolina.
What contaminants are in Mill Spring's water?
Lead was measured at 0.0 ppb (90th percentile). 1 violation is on record.
How is Mill Spring's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Mill Spring?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Mill Spring's water come from?
Mill Spring's water is sourced from Purchased surface water. The city has 1 water system serving approximately 838 residents.
How does Mill Spring's water compare to other cities?
Mill Spring ranks #8 out of 195 cities in South Carolina (better than 96% of state cities) and #392 out of 15382 cities nationally (98th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Mill Spring's small water system affect quality?
Mill Spring's system serves approximately 838 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 1 violation on record.