The data, cited
An ongoing aggregation of Summerville Commissioners of Public Works data, EWG testing, EPA rulings, and news coverage -- so you can see what a local water-treatment decision is based on, not what a salesperson wants you to believe.
The detections
Which PFAS compounds have been detected in Summerville tap water?
Five. PFUnA at 7.1 ppt (1,183 times the EWG health advisory), PFDoA at 4.5 ppt (75 times), HFPO-DA (GenX) at 8.0 ppt (approaching the 10 ppt EPA MCL), PFHxA at 2.7 ppt, and PFPeA at 3.3 ppt. Detected levels are below current federal MCLs where federal MCLs exist; EWG health advisory levels are voluntary and typically much lower.
Source: EWG Tap Water Database, PWSID SC1810003, data period 2014-2023
PFAS -- per- and polyfluoroalkyl substances -- are the so-called "forever chemicals." They resist breakdown in water, soil, and the human body. The five compounds below are what EWG and EPA UCMR 5 monitoring have confirmed in Summerville CPW sampling. Multipliers compare the detected concentration to EWG's voluntary health advisory; they are not federal violations. The utility currently meets all federal Safe Drinking Water Act standards.
Compound 01
Detected
7.1 ppt
Vs. EWG advisory
1,183x
EWG: 0.006 ppt
What it is
A long-chain perfluoroalkyl acid from industrial manufacturing, firefighting foam runoff, and textile treatments. Not removed by conventional water treatment.
Why it matters
The single highest multiplier in the Summerville CPW dataset. No individual federal MCL yet; covered under EPA's 2024 proposed PFAS Hazard Index.
Compound 02
Detected
4.5 ppt
Vs. EWG advisory
75x
EWG: 0.06 ppt
What it is
Another long-chain PFAS, chemically similar to PFUnA. Persists in the environment and bioaccumulates in the body.
Why it matters
No individual federal MCL. Associated in peer-reviewed research with thyroid and liver effects at chronic exposure.
Compound 03
Detected
8.0 ppt
Vs. EWG advisory
near 10 ppt MCL
EWG: Under EPA MCL
What it is
A "replacement" PFAS introduced after PFOA was phased out. Marketed as safer; later classified as similarly persistent.
Why it matters
EPA 2024 rule sets the MCL at 10 ppt for GenX. Summerville detection at 8.0 ppt is near the compliance threshold.
Compound 04
Detected
2.7 ppt
Vs. EWG advisory
no federal MCL
EWG: No federal MCL
What it is
A short-chain PFAS. Shorter-chain compounds clear the body faster than PFOS/PFOA but are still persistent in water.
Why it matters
No individual federal MCL. Included in EPA's PFAS mixture analysis under the Hazard Index approach.
Compound 05
Detected
3.3 ppt
Vs. EWG advisory
no federal MCL
EWG: No federal MCL
What it is
A short-chain PFAS, structurally similar to PFHxA. Detected in surface water across the Southeast.
Why it matters
No individual federal MCL. Monitored as part of ongoing PFAS surveillance by EPA.
Source: EWG Tap Water Database, Summerville Commissioners of Public Works (PWSID SC1810003), data period 2014-2023. Verify at ewg.org/tapwater. Multipliers reflect detected levels divided by EWG voluntary health advisory thresholds; they do not represent legal violations.
The remediation project
The utility acknowledges the problem in its own public communications and is spending to fix it. Home filtration is the interim measure while the public infrastructure catches up.
7 ppt
PFAS in Lake Moultrie source water (combined)
Vs. EPA MCL of 4 ppt for PFOA and PFOS combined.
$96M
Total regional project budget
Santee Cooper Regional Water System treatment upgrade. GAC is the primary candidate technology.
$43.5M
Summerville CPW's share (45.3%)
Funded via the August 2024 12.2% rate increase and settlement proceeds from 3M and DuPont litigation.
2029 - 2031
Expected completion window
Original 2029 EPA compliance deadline; EPA has signaled intent to extend to 2031.
The PFAS project sits inside a $168 million 10-year capital program at CPW. Alongside the $43.5 million PFAS share, the plan includes a $75 million second transmission main from Lake Moultrie (explicitly to eliminate the single-point-of-failure exposed by the March 2026 boil water advisory) and a $40 million package of wastewater treatment plant expansion and Sawmill Branch projects. Debt service on the program is projected at roughly $1.75 million per year by 2025.
Sources: Post and Courier, April 2024 ("Forever chemical clean up to bring rate hikes"); Summerville CPW PFAS page. Verify at postandcourier.com and summervillecpw.com/pfas.
March 16 - 20, 2026
What caused the March 2026 Summerville boil water advisory?
An independent contractor, not affiliated with Santee Cooper, punctured a 48-inch underground water main at the Lake Moultrie Regional Water Plant on the evening of March 16, 2026, while operating heavy equipment in a utility easement without permission. The advisory was formally issued March 17 and lifted at approximately 6:28 AM on March 20 after a mandatory 24-hour testing period confirmed water samples passed all safety tests.
Source: Post and Courier and ABC News 4 reporting, March 17-20, 2026
Evening, March 16
48-inch main punctured at Lake Moultrie Regional Water Plant, Moncks Corner.
March 17
Boil water advisory formally issued for Summerville CPW, Goose Creek, Dorchester County Water Authority, and Berkeley County between Moncks Corner and Goose Creek.
Approx. 4:15 AM, March 18
Repair physically completed. A mandatory 24-hour water-sample testing window begins.
Approx. 6:28 AM, March 20
Advisory officially lifted after a second round of samples passed all safety tests.
A single 48-inch supply main serves Summerville, Goose Creek, Dorchester County Water Authority, and parts of Berkeley County. When it goes down, the whole region goes with it. The $75 million second transmission main in CPW's 10-year capital plan is a direct response to that single-point-of-failure. Until it is built, the region remains exposed to the same pattern.
Sources: Post and Courier, ABC News 4 (issued), ABC News 4 (lifted). Deputy CEO Mike Finissi, Santee Cooper, described the event as a "significant break and significant repair."
The basics
5.5 - 7.2 gpg
Hardness (grains per gallon)
Moderately hard. Below SC average of 8.1 gpg; well below national average of 13 gpg.
Lake Moultrie
Source water
Surface water supplied wholesale by Santee Cooper Regional Water System since October 1994.
Chloramine
Secondary disinfectant
Used to minimize formation of disinfection byproducts (TTHMs, HAAs) in the distribution network.
SC1810003
Summerville CPW PWSID
The public water system identifier. Use this to look up CPW on any state or federal water database.
Source: Summerville CPW Consumer Confidence Report (most recent monitoring period January 1 through December 31 of the prior calendar year). Verify at summervillecpw.com/waterqualityreport.
Closer to home
Same Lake Moultrie source, different utilities and different distribution paths. Here is the per-neighborhood view.
Summerville -- Nexton
Served by Summerville CPW and Berkeley County Water and Sanitation depending on section.
Read the Nextonpage ->Summerville -- Cane Bay
Primarily Berkeley County Water and Sanitation. Same Lake Moultrie source water as CPW.
Read the Cane Baypage ->Summerville -- Carnes Crossroads
Primarily Berkeley County Water and Sanitation. Shares the Lake Moultrie PFAS profile.
Read the Carnes Crossroadspage ->Independent verification
Every number on this page came from a public source. Here is where those sources live, so you do not have to take our word for any of it.
Source 01
The Environmental Working Group aggregates utility test data and compares detected contaminant levels against their own health advisory thresholds.
Search "Summerville CPW" or use PWSID SC1810003.
Verify at ewg.org->Source 02
The April 2024 federal rule setting enforceable PFAS limits: 4 ppt for PFOA and PFOS, 10 ppt for HFPO-DA/GenX, PFNA, and PFHxS. EPA has signaled intent to extend compliance to 2031.
Verify at epa.gov->Source 03
The utility's own annual water quality report. Published every spring covering the prior calendar year of monitoring.
Most recent report covers January 1 through December 31 of the prior year.
Verify at summervillecpw.com->Source 04
The utility's public-facing statement on PFAS in Lake Moultrie source water and the Santee Cooper treatment project.
Verify at summervillecpw.com->Source 05
The South Carolina state agency regulating drinking water and private wells. Provides residential well testing kits.
Verify at scdes.sc.gov->Source 06
Verify NSF/ANSI certification claims for any water filtration product by manufacturer and model number.
Verify at info.nsf.org->Questions we hear
According to the EWG Tap Water Database (PWSID SC1810003, data period 2014-2023), Summerville CPW water contains 23 detected contaminants, 11 of which exceed EWG health advisory levels. The highest multipliers are PFUnA at 1,183 times the EWG advisory, haloacetic acids (HAA9) at 368 times, total trihalomethanes at 168 times, and HAA5 at 113 times. All detected levels are below legal federal limits under the Safe Drinking Water Act; the system has no MCL violations as of the 2024 Consumer Confidence Report.
Summerville CPW meets every federal Safe Drinking Water Act standard and has no MCL violations as of the 2024 Consumer Confidence Report. The distinction local researchers draw is that federal MCLs have not been updated for most contaminants in nearly 20 years, and the EWG's voluntary health advisory levels are often much lower. The utility itself recommends, on its own PFAS page, that customers may use home or countertop filters to reduce PFAS exposure while the $96 million Santee Cooper remediation project is being built.
On the evening of March 16, 2026, an independent contractor operating heavy equipment in a Santee Cooper utility easement without permission punctured a 48-inch underground water main at the Lake Moultrie Regional Water Plant near Moncks Corner. The advisory was formally issued March 17 and lifted at approximately 6:28 AM on March 20 after a mandatory 24-hour testing period. Post and Courier reported approximately 200,000 residents affected across Summerville CPW, City of Goose Creek, Dorchester County Water Authority, and Berkeley County. Schools impacted included Cross Elementary, Cross High, Whitesville Elementary, Nexton Elementary, and Cane Bay area schools.
Perfluoroundecanoic acid (PFUnA) is a long-chain perfluoroalkyl acid used historically in industrial manufacturing, firefighting foam, and textile treatments. It is not removed by conventional municipal water treatment. Summerville CPW's detected level is 7.1 parts per trillion against an EWG health advisory of 0.006 ppt -- a multiplier of 1,183 times. There is no individual federal Maximum Contaminant Level for PFUnA yet; it is covered under EPA's 2024 proposed PFAS Hazard Index approach.
Summerville CPW water is moderately hard, measured at 5.5 to 7.2 grains per gallon depending on source and season. That is below the South Carolina state average of 8.1 grains per gallon and well below the national average of 13 grains per gallon. Source: 2024 Summerville CPW Consumer Confidence Report. Moderately hard water is where visible scale on fixtures, soap-performance issues, and accelerated appliance wear begin to show.
Yes. Summerville CPW's 2024 water sampling, confirmed by EWG Tap Water Database data, shows five PFAS compounds detected: PFUnA at 7.1 ppt, PFDoA at 4.5 ppt, HFPO-DA (GenX) at 8.0 ppt, PFHxA at 2.7 ppt, and PFPeA at 3.3 ppt. Lake Moultrie source water contains approximately 7 ppt combined PFAS versus an EPA MCL of 4 ppt for PFOA and PFOS. A $96 million Santee Cooper remediation project is underway to install granular activated carbon treatment, with expected completion between 2029 and 2031.
Summerville CPW raised water and sewer rates 12.2 percent effective August 2024, with water rising from $23.23 to $25.50 per month for a 6,000 gallon household. Source: Post and Courier reporting. The increase funds CPW's $43.5 million share of the $96 million Santee Cooper PFAS remediation project, as well as a broader $168 million 10-year capital program that includes a $75 million second transmission main to eliminate the single-point-of-failure highlighted by the March 2026 boil water advisory.
Summerville CPW is part of a $96 million regional PFAS remediation project led by Santee Cooper Regional Water System, the wholesale supplier that sources Summerville's water from Lake Moultrie. CPW's share is $43.5 million (approximately 45.3 percent). The project will install new treatment infrastructure, with granular activated carbon (GAC) as the primary candidate technology under evaluation. Expected completion is 2029 to 2031 depending on the final EPA compliance deadline. Part of a broader $168 million 10-year capital program at CPW.
What we do with this
We will come to your kitchen counter, show you what is in YOUR tap (not the regional average), and tell you honestly whether a system makes sense for your specific home. If it does not, we will tell you that.
This page will keep updating as new CCRs publish, new EPA rulings land, and new events happen. The next time a main breaks or a PFAS number changes, we add it here with the citation.
