The Pima County Regional Wastewater Reclamation Department (RWRD) provides design, management, and maintenance of the sanitary sewer system for all of Pima County, including the conveyance system and treatment system. The department manages three major metropolitan wastewater treatment plants and eight outlying facilities.

• 2007 Annual Report
• See Divisions for a detailed description of RWRD sections.

Conveyance System

The overall Pima County wastewater conveyance system presently collects more than 70 million gallons per day (mgd) throughout the county’s 370 square mile sanitary service area, which includes the City of Tucson; the neighboring towns of Marana, Oro Valley, and Sahuarita; and unincorporated communities such as Summerhaven (Mt. Lemmon), Arivaca Junction, Avra Valley, Green Valley, Corona de Tucson, and Catalina. The conveyance system consists of more than 3300 miles of public sanitary sewers.

• Map of Major Conveyance Lines

Pima County's sewer pipe system was built using various materials including reinforced concrete, asbestos cement, ductile iron, salt glazed clay, vitrified clay, plastic truss, and polyvinyl chloride (PVC). In Pima County, clay pipe represents 48% of the entire collection system. RWRD's Conveyance Division maintains the 3300+ miles of sewer pipe utilizing a computerized maintenance management system (CMMS) to manage all preventive and unscheduled maintenance.

Treatment System

RWRD's eleven wastewater treatment facilities have treatment capacity ranging from 0.009 mgd to 41 mgd. The major metropolitan facilities are the Roger Road Wastewater Reclamation Facility, the Ina Road Wastewater Reclamation Facility, and the Randolph Park Wastewater Reclamation Facility. The eight outlying wastewater treatment facilities are Green Valley, Pima County Fairgrounds, Avra Valley, Corona de Tucson, Arivaca Junction, Marana, Mt. Lemmon, and Rillito Vista. Treatment processes include biofiltration (Roger Road), high purity oxygen activated sludge (Ina Road), air activated sludge with nutrient removal, oxygen ditch with and without nutrient removal (Green Valley), and bio-membrane reactor (Randolph Park).

• Map of Treatment Facilities
• Illustrations of typical treatment processes at the Roger Road Wastewater Reclamation Facility

History

Pima County's sewerage system dates from 1900, when the City of Tucson purchased the Tucson Water Company for $110,000; the city's Water and Sewerage Department was created in August 1900. The area's first Wastewater Treatment Facility was placed into service in 1928. The Roger Road Wastewater Treatment Facility was put online in 1951. In 1979, the Pima County Regional Wastewater Reclamation Department assumed responsibility for the operation of all the region's public sewerage facilities. In 2007, the department's name was changed to Pima County Regional Wastewater Reclamation Department. (See Pima County Sewer History for a detailed history of Pima County's sewer system, and Sewerhistory.org, an educational site about the history of sewers around the world, co-sponsored by RWRD.)