Almonte Sanitary District (ASD) is the sewer agency responsible for waste water collection from the homes and businesses in the Almonte neighborhood- an unincorporated area of Mill Valley. Almonte is located generally on the hillside above Tamalpais High School bounded on the West by Stanford and Princeton Ave. [top of the hill], on the East by Miller Ave. and Almonte Blvd., on the North by Gomez, and the South by Shoreline.

Almonte Sanitary District is a governmental Special District. The Sewerage Agency of Southern Marin (SASM), of which ASD is a member, has the sewage treatment responsibility. ASD also has responsibility for trash collection for which Mill Valley Refuse Service currently holds the contract. Property owners within the Almonte community pay their sewer bills via their property tax assessments, and their trash collection directly to Mill Valley Refuse.