The State Water Resources Control Board announced yesterday it will reduce the level of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in drinking water that trigger responses by local water systems. Based on recommendations from the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment the Board lowered response levels to 10 parts per trillion (ppt) for PFOA and 40 ppt for PFOS. Previously, the response level was 70 ppt for the total concentration of the two contaminants combined.