Hardness
Moderately Hard
89.9 PPM · 5.3 GPG
Local water dashboard
Official source aggregationA source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Charleston County.
At a glance
EPA quarter 2026Q2
Hardness
Moderately Hard
89.9 PPM · 5.3 GPG
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
2.4e-4 mg/L
2% of action level
Utility match
2 systems
Serves 713 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
89.9 PPM
Parts per million
89.9
mg/L as CaCO₃ equivalent
Grains per gallon
5.3
1 GPG ≈ 17.1 PPM
What this means at home
At 89.9 PPM, mineral scale can build up on fixtures and heating elements, reduce soap lather, and leave visible spotting. Hardness is primarily an aesthetic and appliance concern—not itself a tap-water safety rating.
USGS sites used
39
Nearest site
8.5 mi
Observation range
Jun 26, 2018–Nov 14, 2019
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: CHN- 100 (Well).USGS source documentation ↗
Regional context
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Awendaw median
90 PPM
About the same1 indexed ZIP readings · Range 89.9–89.9 PPM
South Carolina median
19 PPM
71 PPM higher236 indexed ZIP readings · Range 4.2–106 PPM
EPA benchmark screen
Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.
Lead (PB90)
2.4e-4 mg/L
Reported Dec 31, 2024
Copper (CU90)
Not available
No numerical 90th-percentile result
Numerical coverage
1 comparable result
Missing values remain blank; absence is not treated as a pass.
Measured in mg/L
Local 2.4e-4
EPA limit 0.015
100% line = listed limit
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Consumer Confidence Rule | SC1010504 | Unaddressed | Oct 1, 2025 |
| Consumer Confidence Rule | SC1070963 | Unaddressed | Oct 1, 2025 |
| LEAD AND COPPER RULE REVISIONS | SC1070963 | Resolved | Oct 17, 2024through Oct 17, 2024 |
| LEAD AND COPPER RULE REVISIONSHealth-based | SC1070963 | Resolved | Oct 17, 2024through Oct 17, 2024 |
| Lead and Copper Rule | SC1010504 | Resolved | Oct 1, 2023through Jul 24, 2024 |
No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.
Solutions matcher
Matched to Awendaw ZIP 29429 using 89.9 PPM nearby hardness and 1 reported measurement benchmarks.
No urgent match
This profile does not trigger a treatment recommendation. Test at the tap before investing in equipment.
Affiliate disclosure: we may earn a commission from qualifying purchases, at no added cost to you. Product matching is educational and does not replace certified water testing.
Frequently asked
EPA ECHO shows no active health-based violation for the associated systems in this reporting snapshot. This does not prove every contaminant is absent; federal records can lag and household plumbing can change tap conditions.
Nearby USGS observations produce an estimate of 89.9 PPM, or 5.3 grains per gallon, classified as moderately hard. This is not a household tap measurement.
There is no high-hardness trigger in this profile. Confirm with a tap test before buying equipment.