Charleston Water System provides clean, safe, award-winning drinking water that meets or exceeds all state and federal regulatory requirements.
It is continually tested during the treatment process and throughout our water distribution system to ensure quality. Our lab performs thousands of water analyses per month. A summary of each year's water quality testing is provided in our annual water quality report, also known as the Consumer Confidence Report (CCR). This report is published each May and posted on this page.
Common water quality concerns
Changes in water taste, smell, or color may be caused by a variety of factors, including plumbing problems, nearby construction, or changes in our source water, etc.
The most common water quality concerns are listed below. In rare cases, such as after a large water main break or wide-scale loss of system pressure, we may issue a boil water advisory as a precaution. Learn more about boil water advisories
Mineral deposits can accumulate inside of some water mains. Most of the time this isn't a problem, but changes in water pressure resulting from construction activity or the use of fire hydrants can cause these deposits to break loose and dissolve in the water, resulting in discoloration.
In many cases, our crews can eliminate most of the discolored water by opening nearby fire hydrants to flush the discolored water from the pipe. However, if you experience discolored water, let your faucet run until the water appears clear. If the problem persists, contact us by calling 727-6800.
Rotten egg odor
A rotten egg odor is typically caused by one of three things in your home’s plumbing system: Sulfur-producing bacteria in your water heater, a dried up S-trap in an unused sink, or decaying food in a kitchen sink disposal.
If you only notice the odor when you use hot or warm water, it’s probably your water heater. Consult the owner’s manual for instructions on how to flush it.
If the problem occurs in an unused bathroom, turn on the tap to fill the S-trap. If the odor is in the kitchen only, try cleaning the drain disposal.
Pink or black growth on faucets, around drains, etc.
Pink staining and black growth are both are caused by airborne microorganisms that thrive in warm, moist areas such as bathrooms and laundry rooms—not by anything in the water.
Some people observe a black gunk on their faucets and in toilets. This is a type of mold that grows rapidly in dark, humid places, producing a black string-like material that can break loose and hang from faucets.
Pink film that typically appears around drains is caused by airborne bacteria that also thrive in moist areas, such as sinks, toilets, and bathtubs.
The best way to combat both is frequent cleaning with a bleach solution. Make sure you have proper ventilation in bathrooms, and repair dripping faucets to keep the area around drains dry.
Earthy-musty taste and smell
In the Spring and sometimes in the Fall, our tap water may develop what's most often described as an "earthy" or "musty" taste and smell. This is caused by natural changes in our source water. It is temporary and harmless.
It's caused by blue-green algae in the Bushy Park Reservoir, our primary water source. Algae produce two harmless compounds, MIB and Geosmin, which have a distinctive earthy-musty taste and odor. (Geosmin is found in beets—it gives beets their earthy flavor.)
People’s sensitivity varies, but the human nose can detect these compounds in quantities as small as 5 parts per trillion. We monitor MIB and Geosmin levels closely and track customer complaints to determine when to adjust the treatment process to minimize the earthy-mustiness.
You can also try refrigerating a pitcher of tap water—taste is less noticeable in cold water.
To report a taste and odor concern, e-mail us or call our Customer Service Center at 843-727-6800.
The Bushy Park Reservoir, CWS's primary water source.
Request a water quality test
If you have a water quality concern or would like to request a water quality test, please call our Customer Service Department at (843) 727-6800 or send us an e-mail.
Charleston Water System reduces the corrosiveness of our water during the treatment process, which prevents lead from old plumbing from leaching into your water. However, if your home has old plumbing and/or solder, and you would like to test your water for lead, we offer testing free of charge. Just pick up a testing kit at our downtown or North Area office locations. Learn more about lead and drinking water