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Tap water quality report

Johns Island (Sta.), SC

EPA monitoring detected 20 contaminants across the 2 water suppliers serving Johns Island (Sta.). A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

2
water suppliers
32,142
people served
20
contaminants found
South Carolina rankings Lead in South Carolina PFAS in South Carolina

What was found in Johns Island (Sta.)'s water

The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Copper
117 µg/L 9%
of the EPA limit 1300 µg/L
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
Total Haloacetic Acids (HAA5)
40.8025 µg/L 68%
of the EPA limit 60 µg/L
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
TTHM
23.506 µg/L 29%
of the EPA limit 80 µg/L
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
Highest in the city: 31.0635 µg/L — KIAWAH ISLAND UTILITY (SC1010008) · 9,550 people · 2019
2/2 SYR4
Dichloroacetic Acid
30.019 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
Bromoform
13.078 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
Highest in the city: 13.215 µg/L — KIAWAH ISLAND UTILITY (SC1010008) · 9,550 people · 2019
2/2 SYR4
Chloroform
10.445 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
Highest in the city: 12.0535 µg/L — KIAWAH ISLAND UTILITY (SC1010008) · 9,550 people · 2019
2/2 SYR4
Dibromoacetic Acid
9.818 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
Monochloroacetic Acid
8.925 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
Dibromochloromethane
6.27 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
Highest in the city: 7.75 µg/L — KIAWAH ISLAND UTILITY (SC1010008) · 9,550 people · 2019
2/2 SYR4
Bromodichloromethane
7.7105 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
Lead
6.255 µg/L 42%
of the EPA limit 15 µg/L
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
Trichloroacetic Acid
5.151 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
Highest in the city: 5.662 µg/L — KIAWAH ISLAND UTILITY (SC1010008) · 9,550 people · 2019
2/2 SYR4
Monobromoacetic Acid
3.997 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2019
2/2 SYR4
Pfba
0.0087 µg/L
No EPA limit set
Highest in the city: KIAWAH ISLAND UTILITY (SC1010008) · 9,550 people · 2023
1/2 UCMR-5
PFOS
0.0085 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2025
2/2 UCMR-5
Pfpea
0.0056 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2025
Highest in the city: 0.0076 µg/L — KIAWAH ISLAND UTILITY (SC1010008) · 9,550 people · 2023
2/2 UCMR-5
PFOA
0.0054 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2025
2/2 UCMR-5
Pfhxa
0.0049 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2025
2/2 UCMR-5
PFBS
0.0045 µg/L
No EPA limit set
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2025
2/2 UCMR-5
Lead
0.0020 mg/L 13%
of the EPA limit 0.0150 mg/L
Main supplier: ST JOHN'S WATER (SC1020002) · 22,592 people · 2025
2/2 LCR
Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Johns Island (Sta.)

SupplierPopulation served
ST JOHN'S WATER (SC1020002) 22,592
KIAWAH ISLAND UTILITY (SC1010008) 9,550

Frequently asked questions about Johns Island (Sta.) tap water

Is Johns Island (Sta.) tap water safe to drink?

EPA testing detected 20 contaminants in the water serving Johns Island (Sta.). A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Johns Island (Sta.)?

2 public water suppliers report drinking-water monitoring for Johns Island (Sta.), South Carolina to the EPA. Each is listed above with its population served.

What contaminants are in Johns Island (Sta.)'s water?

The contaminants EPA monitoring detected in Johns Island (Sta.) include Copper, Total Haloacetic Acids (HAA5), TTHM, Dichloroacetic Acid, Bromoform. The full list, with the level at the main supplier and the data source, is in the table above.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.