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Charleston Water System (sc1010001)

Charleston, SC · serves 242,397 · Surface waterSC1010001
Action recommended
PFAS detected above the federal limit. Utilities have until 2029 to install treatment; until then, a certified filter handles it at the tap.
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Measured in your 2025 water report
From your utility's Consumer Confidence Report · 11 contaminants tested
Above limit
Approaching limit
Within limits
Regulated contaminants — legally enforceable limits
DEHP▸
0.0037 mg/L
No additional information available for this contaminant.
Gross Alpha▸
0.376 pCi/L
What is it?
A screening test that measures total alpha radiation from all radioactive elements in water — including radium, uranium, and radon.
Why it matters
The MCL of 15 pCi/L protects against long-term cancer risk from radiation exposure.
What to do
No action needed at typical detection levels. If near the MCL, reverse osmosis and ion exchange filters can reduce radioactive contaminants.
Nitrate (as N)▸
0.14 mg/L
What is it?
Comes from fertilizer runoff, septic systems, and erosion of natural deposits. One of the most common groundwater contaminants in agricultural areas.
Why it matters
Nitrate above 10 mg/L can cause "blue baby syndrome" (methemoglobinemia) in infants under 6 months — it interferes with blood's ability to carry oxygen. Adults can tolerate higher levels.
What to do
If you have an infant on formula and your water is above 5 mg/L, consider using bottled water for formula preparation. Boiling water does NOT remove nitrate — it concentrates it.
What the research says
Multiple peer-reviewed studies have found neural tube defects, preterm birth, and low birth weight at concentrations as low as 5 mg/L — 2x below the US federal limit.
Selenium▸
0.0037 mg/L
What is it?
A naturally occurring element essential in small amounts but toxic at high levels. Enters water from erosion of natural deposits and discharge from mines and refineries.
Why it matters
Long-term exposure above the MCL of 0.05 mg/L can cause hair and fingernail loss, numbness, and circulation problems.
What to do
No action needed at typical detection levels. Selenium is rarely found near its MCL in treated water.
Lead & copper — tested at your tap
Copper▸
0.089 mg/L
What is it?
Leaches from copper household plumbing and pipes. Some copper is a normal part of drinking water infrastructure.
Why it matters
Short-term exposure above the action level of 1.3 mg/L can cause gastrointestinal distress. Long-term exposure can cause liver and kidney damage. At typical detected levels (well below the AL), copper is not a health concern.
What to do
If above the action level, run your tap for 30 seconds before drinking. Copper levels decrease as water flows through the pipes.
Lead▸
0.0035 mg/L
What is it?
Lead in drinking water almost always comes from your home's plumbing — not from the water source or treatment plant. Lead pipes, solder, and brass fixtures can leach lead, especially if water sits in pipes for hours.
Why it matters
There is no safe level of lead exposure. Even low levels can harm children's brain development, and cause kidney and blood pressure problems in adults. The action level of 15 µg/L is a regulatory trigger, not a safety threshold.
What to do
Run your tap for 30 seconds to 2 minutes before drinking, especially in the morning. Use cold water for cooking and formula — hot water leaches more lead. A filter certified to NSF/ANSI 53 for lead removal is the most reliable protection.
What the research says
There is no safe level of lead exposure. Lead crosses the placenta and causes preterm birth and cognitive impairment in children at blood lead levels below 10 µg/dL.
Disinfection byproducts
HAA5▸
13 µg/L
What is it?
Another group of disinfection byproducts formed when chlorine reacts with natural organic matter. HAA5 measures the five most common species.
Why it matters
Long-term exposure above the MCL of 60 µg/L (0.060 mg/L) is associated with increased cancer risk. Like THMs, the MCL is based on a running annual average.
What to do
Activated carbon filters can reduce HAA5. If your system consistently approaches the limit, a reverse osmosis filter provides more complete removal.
TTHM▸
12 µg/L
What is it?
Formed when chlorine used to disinfect water reacts with natural organic matter. Includes chloroform, bromoform, and related compounds. The trade-off: disinfection prevents waterborne disease, but creates these byproducts.
Why it matters
Long-term exposure above the MCL of 80 µg/L (0.080 mg/L) is associated with increased cancer risk and possible reproductive effects. The MCL is based on a running annual average, not a single sample.
What to do
If your system is near or above the limit, an activated carbon filter (including pitcher filters like Brita) can reduce THMs. Running water for a minute before drinking also helps, as THMs are volatile and dissipate.
Disinfectants — MRDL
Chlorine▸
3 mg/L
What is it?
Added intentionally to kill bacteria and viruses. A chlorine residual in your tap water means the disinfection is still active through the distribution system — this is by design.
Why it matters
The MRDL of 4 mg/L is the maximum allowed. Typical levels are 0.5–2 mg/L. Chlorine at normal levels is not a health concern — the disease risk from untreated water is far greater.
What to do
If you don't like the taste, let water sit in an open pitcher for 30 minutes or use an activated carbon filter. Both remove chlorine taste and odor.
OTHER
Highest single measurement▸
0.09
No additional information available for this contaminant.
Lowest monthly % meeting limit▸
100
No additional information available for this contaminant.
% of limit

CCR data in early access — values are extracted from utility PDFs and may contain errors. Verify with your utility's 2025 CCR report.

Source: CHARLESTON WATER SYSTEM (SC1010001) Consumer Confidence Report 2025 · Extracted by WaterScore
Measured data
Private Well Risk

Do you have or use a private well? Measured concentrations from nearby private wells sampled within 5 miles.

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2 sites within 10 mi
Nearby Superfund Sites

2 EPA Superfund sites within 10 miles. Proximity does not necessarily mean your water is affected.

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Surface water
Water Sources

Charleston draws from surface water — Edisto River (S10101) and Bushy Park Reservoir (S10104). Drought directly affects reservoir levels and river flow. ⚠️ This region is currently under severe drought conditions — reservoir and river levels may be reduced.

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Spatial context
Your area on the map
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