Charleston County tap water: hardness, PFAS and lead
Charleston County, South Carolina has about 431,001 residents (Census 2024 estimate) and 15 community water systems in EPA records. The largest local system is Charleston Water System (Sc1010001), serving about 278,771 people from surface water.
! 1 of 6 largest systems with health-based violationsPFAS detected at 6 of 6 sampled systemsHardness 4.9 gpg (low confidence)
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
How hard is Charleston County water?
Charleston Water System (Sc1010001)Estimate: untreated local water, not your tap · Low confidence
4.9 gpg(84 mg/L), moderately hard
Charleston County: median of 596 results from 147 monitoring sites (streams and wells). Utilities may blend or treat water, so your tap can differ.
County estimates: Hard Water Map (hardwatermap.com), CC BY 4.0, derived from the USGS/EPA Water Quality Portal; file generated 2026-07-22. License
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
Softener size at 4.9 gpg
For a 3-person home using 57 gallons per person per day and regenerating weekly, you'd remove about 5,865 grains between regenerations. Suggested size: 24,000 grain. This uses a low-confidence county estimate, so confirm with a test first.
Estimate only. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
The 6 biggest of 15 community water systems on EPA records for this county. Service areas don't follow county lines; your water bill names your provider.
Charleston Water System (Sc1010001)
SC1010001 · serves about 278,771 people · Surface water
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
A PFAS detection is not a violation. Federal limits (4 ppt for PFOA and PFOS) apply to running annual averages, with compliance required by 2029. In May 2026 EPA proposed extending the PFOA/PFOS deadline to 2031 and removing other PFAS limits; not final as of 2026-10-21.
Test your own tap
These are public records for whole systems. Your home's pipes, fixtures and any private well can change what you drink. A certified lab test or a hardness test strip gives you your own numbers. Then use our PFAS and lead filter selector to see which certifications to look for.
Common questions about Charleston County water
Is tap water in Charleston County safe to drink?
1 of the 6 largest systems here have at least one health-based violation in EPA records since October 2021 (see each system below for status). Charleston Water System (Sc1010001)'s most recent lead 90th percentile was 3.5 ppb (2022), below the 15 ppb action level. Public records can't guarantee what comes out of your tap, especially with older plumbing, so a home test is the surest check.
How hard is the water in Charleston County?
There's no published utility figure in our data, but untreated local stream and well samples in Charleston County have a median of about 4.9 grains per gallon (84 mg/L, moderately hard). That's a low-confidence estimate of source water, not your tap, so test before you buy equipment. For a 3-person home at 4.9 gpg, our softener calculator suggests a 24,000 grain unit as a starting point.
Is there PFAS in Charleston County water?
6 of the 6 sampled systems listed here detected at least one PFAS in EPA's UCMR 5 testing, and 12 results were above the level of a federal limit in at least one sample. A detection isn't a violation: federal PFAS limits apply to running annual averages starting in 2029.
Which water system serves my address in Charleston County?
Most homes are served by Charleston Water System (Sc1010001) or one of the other systems listed on this page, but service areas don't follow county lines. Your water bill names your provider, and its annual Consumer Confidence Report has the full test results.
Data as of October 21, 2026. Figures are copied from public records and combined with our own calculations; they can be out of date or wrong. Tapped Out isn't affiliated with any utility or the EPA. Written and reviewed by the Tapped Out team. How we calculate · All sources.