What's Really in Charleston's Tap Water?
If you live in the Charleston, SC area, your tap water comes from the Charleston Water System (CWS), which sources water from the Bushy Park Reservoir and the Edisto River. While the water meets federal standards, that doesn't always mean it's free from concerning contaminants.
What the EWG Found
According to the Environmental Working Group's Tap Water Database, Charleston's water has tested positive for several contaminants that exceed EWG's health guidelines, even though they may fall within EPA legal limits.
Key contaminants detected include:
- Haloacetic acids (HAA5 & HAA9): Disinfection byproducts formed when chlorine reacts with organic matter. Linked to increased cancer risk in long-term studies.
- Total trihalomethanes (TTHMs): Another group of disinfection byproducts, including chloroform. The EWG health guideline is significantly lower than the federal legal limit.
- Chloramine: Used as the primary disinfectant by CWS. Harder to remove than chlorine with standard filters.
- Hardness minerals: Charleston water ranges from moderately hard to hard (7-10 GPG), causing scale buildup and dry skin.
Important: "Legal" doesn't always mean "safe." EPA legal limits are often set based on what's feasible for utilities to achieve, not solely on health impacts. The EWG sets stricter health-based guidelines using the latest scientific research.
Chloramine in Charleston
Charleston Water System uses chloramine (a combination of chlorine and ammonia) as its disinfectant. While effective at killing bacteria over long pipe runs, chloramine presents unique challenges:
- Standard carbon filters (like Brita) may not effectively remove it
- Can corrode rubber seals and certain metals in plumbing
- Harmful to fish and aquatic life in aquariums
- Some individuals report skin irritation from showering in chloraminated water
What You Can Do
The first step is knowing exactly what's in YOUR water. While city-wide reports give a general picture, water quality can vary significantly from home to home based on the age and material of your pipes, distance from the treatment plant, and other factors.
A free in-home water test gives you specific, actionable data about your water. From there, you can make an informed decision about whether filtration makes sense for your family.