City hydrants being flushed for lead corrosion treatment

The Pittsburgh Water and Sewer Authority has begun opening street hydrants and flushing water mains in some city neighborhoods in anticipation of adding a new lead corrosion control chemical to the water supply.

The authority announced Monday that it has applied to the state Department of Environmental Protection for approval to begin using orthophosphate, instead of soda ash and lyme, to reduce corrosion in the city’s lead service lines.

“Orthophosphate addition is the interim step to reduce the risk of lead in water found in some homes,” PWSA executive director Robert A. Weimar stated in a news release. “Our long-term goal is to remove all lead service lines from the system.”

The authority expects to begin its lead water service line replacement program in the next few weeks and replace approximately 4,500 lines by June of next year.

The chemical switch, which the DEP is expected to approve within 20 days, according to Will Pickering, a PWSA spokesman, was recommended after a yearlong study found orthophosphate does a better job coating the inside of lead service lines than soda ash or other chemicals tested.

Mr. Pickering said the DEP required the study in 2016 after the state agency found PWSA was using caustic soda as an anti-corrosive additive in 2014 instead of soda ash and lime as its operating permit specified.

The switch likely caused city water lead levels to exceed the U.S. Environmental Protection Agency

drinking water standards in 2016. An estimated 20 to 25 percent of the PWSA’s 83,000 customers may have lead service lines.

Orthophosphate is described by the authority as a food-grade additive that forms a protective layer between lead service lines and the water they carry. It is approved by the EPA and, Mr. Pickering said, used extensively in cities where lead lines are a problem, including Washington, D.C., and sections of Pittsburgh served by the Pennsylvania American Water Co.

“Orthophosphate creates a physical coating in lead pipes that will take some time to occur,” Mr. Pickering said. “It could be several months before we begin to see lead water levels decrease, but we’ve also heard of places where it’s dropped within weeks.”

Mr. Pickering said the DEP has already been in town inspecting the four orthophosphate additive facilities. Two are located around the Highland Park Reservoir, one at the Aspinwall Treatment Plant and another at the Bruecken Pump Station, across the Allegheny River from Aspinwall.

The main line flushing began March 18 and is scheduled to run through Friday in the city neighborhoods of Esplen, Elliott, West End, Duquesne Heights, Mount Washington, Allentown, South Side Slopes, Squirrel Hill South, Greenfield, Hazelwood, Glen Hazel and small portions of Sheraden, Westwood and Ridgemont.

Water will flow from hydrants in other city neighborhoods throughout the distribution system over the next few months to prepare the pipes and make room for the orthophosphate-treated water.

Some water customers may experience temporary brown or discolored water during and after the flushing, the PWSA said in a release announcing the action.

To clear the discolored water, the PWSA advises customers to run cold taps for 10 minutes at the lowest faucet in their homes or buildings until the water runs clear. If that doesn’t fix the problem, open the tap again and repeat. If the problem persists, contact PWSA customer service at 412-2552423.