The addition of a food-grade chemical called orthophosphate to Pittsburgh Water and Sewer Authority’s distribution system is expected to lower lead levels for its 300,000 consumers within months. The change on Monday comes nearly three years after PWSA first exceeded the federal action level for lead in drinking water.
Orthophosphate coats the inside of pipes to form a physical barrier that prevents water from coming into contact with lead. Water authorities across the country, including Pennsylvania American Water, have long used the chemical to prevent metal from leaching into water. PWSA worked with the Pennsylvania Department of Environmental Protection to conduct a lengthy study before it could build the four facilities necessary to add orthophosphate at three points across the system.
“It is really a big deal,” said Will Pickering, PWSA’s senior manager of public affairs. “About 12 to 15 percent of our residential customers still have these lead service lines. We’re working our hardest to replace them as fast as possible,” but orthophosphate will protect people in the interim. The agency expects to replace 4,500 lead service lines in 2019.
Under its agreement with DEP the authority must stagger the addition of orthophosphate across several weeks. The first of three phases began Monday with the portion of the city served by the Highland II reservoir, including parts of Squirrel Hill, Hazelwood and the west end; the South Side, the Central Business District, and Lawrenceville. Pickering said the gradual rollout will allow the agency to closely monitor water quality throughout the transition.
In order to ensure that orthophosphate adheres to its pipes, PWSA will begin to flush transmission mains, distribution mains and fire hydrants to scour away sediment. The flushing also helps move orthophosphate-treated water to homes more quickly, said Pickering. Brown or discolored water may result from this process. PWSA recommends running cold water from the lowest tap in the house for ten minutes or until the water runs clear.
PWSA expects to see lower lead levels by its next round of state-mandated testing in June.