This article discusses a new filtration technology, a polishing sand filter (PSF), that effectively removes iron and manganese; treats water with sulfate‐reducing bacteria (SRB) and hydrogen sulfide (H2S); reduces capital, operating, maintenance, and chemical costs; uses less energy; produces less waste; and, is easy to operate. PSF design enhances traditional slow sand filtration's (TSSF's) polishing capabilities and replaces onerous cleaning processes with a backwash process that doesn't require media to be removed or lost from the filter. A biological layer isn't required for successful operation, allowing loading rates three or more times greater than TSSF and a shallower filter bed, resulting in a more compact filter design.