Philadelphia water department faces class action lawsuit over water testing

City is under increasing pressure to change test methods that scientists said may underestimate the amount of lead found in water after a Guardian investigation

The Philadelphia water department, accused by some experts of having water testing "worse than Flint", is facing a class action lawsuit and a lead-testing campaign mounted by citizens concerned about water quality.

On Thursday, hours after the Guardian published an investigation into the water-testing practices of 33 cities east of the Mississippi river, the Hagens Berman law firm announced a class action lawsuit against Philadelphia, based in part on the city's outdated test practices.