Where Charleston’s Drinking Water Comes From
Before debating filters, hardness, taste, or salt, ask the dull question that actually matters: which utility name is on the water bill?
Two systems
Utility Paths
Reservoir + river
Charleston Water System treats surface water from Bushy Park Reservoir and the Edisto River at the Hanahan Water Treatment Plant.
Aquifer + RO
Mount Pleasant Waterworks draws deep groundwater from the Charleston Aquifer, treats it through reverse osmosis, and supplements supply with treated CWS water.
Sources
The cleanest way to understand local tap water is to follow it backward from the faucet. Charleston’s system points inland toward a reservoir, river, and treatment plant. Mount Pleasant’s points down into the aquifer, then through reverse osmosis treatment, with some CWS water added in the mix.
We do not source our water from Charleston Harbor, that’s not as good an idea as one would think.
Treatment
Surface water
River and reservoir water is treated by settling, filtration, and disinfection.
Deep groundwater
Aquifer water is protected from many surface issues, but dissolved minerals and salts require a different tool.
At the Tap
A utility report describes the public system. It does not inspect any particular home’s service line, water heater, fixtures, or whatever plumbing archaeology lies on that side of the meter.
Your own due diligence will be required to inspect the home’s water systems – and if the home is on the older side, it’s often a good idea to perform an inspection the water lines.
Quick checks:
- Confirm the utility on the bill.
- Read the current utility report.
- Check lead/service-line resources.
- Look at plumbing age and renovation history.
- Test at the tap when the house gives you reason.
Waterways
Tap water is treated infrastructure – creeks, marshes, rivers, and the harbor are all shaped by the movements of stormwater, tides, bacteria, as well as ongoing development and legacy industrial sites.
Utility reports
Water supply is one of those systems that shapes our daily life, though we only think about it when something goes wrong.
During the home buying process, be mindful of where the water is coming from and going to.