Local water supply gets the treatment

For Charleston residents — especially those who remember the local water supply leading the nation in lead contamination — the push to drink from the tap has been met with some skepticism.

Just ask Jenny Hagan, public relations director for the Charleston Water System. At speaking engagements, when she asks where local water comes from, she hears some interesting guesses: The ocean? The sewer?

Charleston's water in fact comes from the Bushy Park Reservoir and the Edisto River, and its lead level is down to less than one-70th what it was during the 1992 scare.

Roughly 400,000 people across the county use about 70 million gallons at peak times, a figure that Andy Fairey, the water system's chief operating officer, calls "a drop in the bucket."

An estimated 2 billion gallons rush through the system's sources each day to keep the water from going stale. Most of it runs through to the ocean.

Here's how it gets to your tap: The raw water first moves to a pump house at the Hanahan Water Treatment Plant just across the line in Berkeley County, where chemical stations add aluminum sulfate. Fairey said the chemical compound clumps together leaves and sand, which wind up in a sediment tank as the water continues. The remaining stream then passes through filtration layers of charcoal, sand and gravel.

Water officials add materials to the filtered water, including fluoride for stronger teeth, and lime to bring down the water's acidity and improve its taste, according to Fairey. To disinfect the water, the Charleston Water System uses two chlorine compounds rather than elemental chlorine, which Fairey said is suspected of producing two cancer-causing chemicals. One of those dangerous chemicals appears at about one-tenth the federal standard and the other at about one-fifth, according to 2007 lab results.

As for lead, Charleston's water contains 3 parts lead per billion, down from an average of 211 parts per billion when

Charleston ranked highest in the country.

Charleston solved its lead problem, in part, with a compound that lines pipes and keeps them from releasing metals into the water, Fairey explained.

Every three years the Charleston Water System pulls a sample from 50 "at-risk" homes known to have lead plumbing.

Those residents submit the first drops of water from their faucets in the morning, when mineral leaching would show most. And they provide the samples during the summer, when the pipes are hottest. "The numbers that get reported are the worst of the worst," Fairey said.

Only one sample proved higher than desired in 2007, according to lab results.

Both the Charleston Water System and the Santee Cooper Regional Water System — which serves Berkeley County, Summerville, Moncks Corner and Goose Creek — meet or exceed all federal and state requirements and belong to a voluntary safe water program. The Santee Cooper system's 2007 report showed the two suspected cancer-causing chemicals at about half the maximum level allowed. None of its samples exceeded the level of lead that would trigger special treatment.

Charleston also tested for 36 pharmaceuticals and personal care products in its water before the Associated Press released an investigation earlier this year that found drugs in water supplies across the country. Lab results showed traces in parts per billion for three compounds: caffeine; a substance found in wood and cleaning products; and a flame retardant.

Hagan called safe tap water "one of the most important public health advances in modern history." But a lingering distrust leads people to turn to bottled products for their drinking supply.

"People just don't value tap water," she said. "But it hasn't been that long ago that people didn't have the convenience and the quality."