Is Mount Pleasant, SC tap water safe?
Supplied by Mt Pleasant Waterworks · serves 91,500 people (44,803 connections) · Purchased surface water · EPA ID SC1010002
Data: U.S. EPA · How we read the data · How we check it
Buys water from Charleston Water System. Treated water bought from another system can carry that system's contaminants.
Summary
PFAS above the 2024 federal limits. Systems have until 2029 to meet the PFAS limits.
Is it an emergency? No: PFAS limits are about years of exposure, not a glass of water, and nothing in EPA's data calls for you to stop drinking the water today. If your utility ever issues a boil-water or do-not-drink notice, follow it.
- PFAS
- Above limitPFOS above the federal limit in EPA's 2023–2025 testing (PFOS 6.63 ppt vs a limit of 4 ppt, where ppt = parts per trillion).
- Lead
- Below action level1 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period Jan 2024 – now, still in progress (results reported so far). Your home's pipes can make yours higher.
- Violations
- None health-basedNo health-based violations since 2016.
- Pregnant, or mixing baby formula with tap water? Babies drink more water for their size, so PFAS exposure matters more for them. Consider bottled water or a filter certified for PFAS for formula, and ask your doctor. Health effects.
- To lower your PFAS exposure now, a home filter certified for PFAS reduction works (reverse osmosis, or activated carbon certified to NSF/ANSI 53 or 58). Filters for these results.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Mt Pleasant Waterworks's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill, and you can also request it at (843) 884-9626. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 5 entry points tested Feb 2024 to Jan 2025. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA One sample above limit Limit 4 ppt | 3.65 ppt 91% of the limit |
| PFOS Above limit Limit 4 ppt | 6.63 ppt 1.66× the limit |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Detected, below limit Limit 1 | 0.0015 |
| PFBS Detected, below limit Guideline 2,000 ppt | 2.93 ppt |
| PFBA Detected, below limit Guideline 6,000 ppt | 2.9 ppt |
| PFHxA Detected, below limit Guideline 3,000 ppt | 3.55 ppt |
| PFPeA Detected, no limit | 5.17 ppt |
For context: the PFOS average is higher than at 80% of the South Carolina systems EPA tested.
29 PFAS tested, 6 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Not detected in 12 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 1 ppb lead (Jan 2024 – now (in progress)). Below action level
Highest since 2016: 2 ppb (Dec 2017).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2024 – now (in progress) | 1 ppb |
| Jan 2021 – Dec 2023 | 1.1 ppb |
| Jan 2018 – Dec 2020 | 0.66 ppb |
Earlier results (9)
| Jan 2015 – Dec 2017 | 2 ppb |
| Jan 2012 – Dec 2014 | 0 ppb |
| Jan 2009 – Dec 2011 | 0 ppb |
| Jan 2006 – Dec 2008 | 0 ppb |
| Jan 2003 – Dec 2005 | 0 ppb |
| Jan 2000 – Dec 2002 | 7 ppb |
| Jan 1997 – Dec 1999 | 5 ppb |
| Jan 1996 – Dec 1996 | 13 ppb |
| Jul 1993 – Dec 1994 | 6 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 10.4 ppb | 300 ppb |
| Vanadium | 1 ppb | 21 ppb |
| Chlorate | 240 ppb | 210 ppb |
| Strontium | 0.056 ppm | 1.5 ppm |
| 1,4-Dioxane | 0.32 ppb | 0.35 ppb |
| Chromium-6 | 0.056 ppb | – |
Where it serves
Mount Pleasant
ZIP codes the system reported serving: 29429, 29464, 29465, 29466
Nearby utilities
- Charleston Water System Charleston · 6 mi · PFAS above limit
- Isle of Palms Water & Sewer Commission Isle of Palms · 7 mi · PFAS above limit
- City of Folly Beach Folly Beach · 11 mi · PFAS above limit
- Dcws Ashley Phosphate Water System North Charleston · 14 mi · PFAS above limit
- Kiawah Island Utility Kiawah Island · 17 mi · PFAS above limit
- Dcwa Calomet Valley Water System Summerville · 23 mi · PFAS above limit
Questions
Is Mount Pleasant tap water safe to drink?
Most of Mount Pleasant gets its water from Mt Pleasant Waterworks. Mt Pleasant Waterworks has no health-based violations since 2016. EPA testing found PFAS above the 2024 federal limits, which systems must meet by 2029. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Mount Pleasant water have PFAS?
Yes. EPA's 2023–2025 testing of Mt Pleasant Waterworks found 6 PFAS at least once. The highest entry-point averages were above the federal limit for PFOS: PFOS 6.63 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in Mount Pleasant water?
The most recent 90th-percentile lead result for Mt Pleasant Waterworks is 1 ppb, for the monitoring period that began Jan 2024 (still in progress). The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for SC1010002: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID SC1010002).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Mt Pleasant Waterworks at (843) 884-9626, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.