Regional Water Recycling Plant No. 4

12811 6th Street
Rancho Cucamonga, California 91739

Regional Water Recycling Plant No.4 (RP-4) is located in the city of Rancho Cucamonga and has been in operation since 1997. The plant has undergone an expansion to increase the design hydraulic domestic sewage (wastewater) treatment capacity to 14 million gallons per day. The plant serves areas of Fontana, Rancho Cucamonga, and San Bernardino County. The plant treats the liquid portion of an average influent wastewater flow of approximately 10 million gallons per day.

The liquid treatment section consists of preliminary screening and grit removal, primary clarification, secondary treatment by aeration basins and clarification, tertiary treatment by filtration and disinfection. Wastewater liquid is treated to State Division of Drinking Water Title 22 Code of Regulations standards for disinfected tertiary recycled water. The solids removed from RP-4 are conveyed by gravity through the regional sewer system to the influent of RP-1 for thickening, anaerobic digestion, and dewatering.

Click here to read about our Wastewater Treatment Process.

Regional Water Recycling Plant #1 Photos
(click to view larger)

Wastewater Treatment Process Diagram

Regional Water Recycling Plant No. 4 Map

Water Recycling Material
EPA Part 503 Biosolids Rule
RP-4 Title 22 Report
RP-4 AQMD Permit to Operate
NPDES Permit
Asset Management Plan 16/17