The Portland Water District acquired the Portland Water Company in 1908. Their main goal was to ensure the purity of the water supply from Sebago Lake to Portland. To that end, the District maintained a well equipped laboratory first on Kennebec Street in Portland, then at their main office at 16 Casco Street in Portland.

The bacteriological laboratory had been in operation for a few years when this photo was taken. It pictures Augustus E. Clark, resident chemist and bacteriologist, standing next to some of the equipment used in the water testing.