A study was made to determine the suitability of three small hydrologic subareas in San Diego County, California, for reuse of treated municipal wastewater (reclaimed water). Groundwater quality has been impacted by agricultural water use, changes in natural recharge patterns, seawater intrusion, and groundwater movement from surrounding marine sediments. Groundwater levels near land surface may limit artificial recharge of reclaimed water or may require pumping of groundwater from the aquifer prior to recharge with reclaimed water. Reclaimed water may be used for irrigated water in upland areas. (USGS)