The Lyon County Wastewater Division provides sewer service to the Dayton area and to the Carson Highlands area in Mound House. 4 treatment plants cover this area.
South Dayton Wastewater Treatment facility serves the Old town Dayton, River Village, Santa Maria, and developments surrounding the Dayton Valley Golf Course.
North Dayton Wastewater Treatment facility serves the Rose Peak and Sutro service area.
Rolling A Wastewater Treatment facility serves the River Park, Canyon Estates, Nantucket, Brookhaven, and excess flows from North Dayton WWTF. In November 2007 the South plant- Rolling A interconnection was completed. This enabled Lyon County to redirect the raw wastewater to Rolling A for treatment. In the interest of conserving resources Lyon County has redirected all the Wastewater to the Rolling A facility and mothballed the South Dayton and North Dayton Wastewater Treatment facilities.
Carson Highlands Wastewater Treatment facility serves only the Carson Highlands subdivision in the Moundhouse area.
Lyon County Wastewater Division also provides sewer service to the Willowcreek GID. This service area is located 4 miles East of Yerington off Highway 95A. Lyon County has a contract with the City of Yerington to perform routine maintenance at this site.
Lyon County took control of operations of the Silver Springs Wastewater Treatment facility in August 2007.