Valley Water weighs septic upgrades and buyouts to unlock 4,200 AF of blocked aquifer recharge

Valley Water weighs septic upgrades and buyouts to unlock 4,200 AF of blocked aquifer rechargeThe Santa Clara Valley Water District is advancing an optimization study to restore capacity at its San Pedro Ponds, where operations have been severely curtailed to prevent groundwater mounding from flooding neighboring private septic systems.

The San Pedro Ponds have a recharge capacity of 4,700 acre-feet per year but currently operate at less than 500 acre-feet.

Operations are restricted by a county health mandate to keep the water table at least 23 feet below the surface to protect half a dozen adjacent properties using legacy septic tanks.

A recent pre-feasibility study by consultant GAI narrowed eight potential solutions down to four top alternatives.

The highest-scoring alternative involves installing alternative wastewater treatment systems at the affected private properties, with sewer connections and property acquisitions also under consideration.

Santa Clara Valley Water District (Valley Water) is reviewing four capital project alternatives to maximize groundwater recharge at its San Pedro Ponds facility in South County. The ponds currently operate at less than 11% of their 4,700 acre-foot annual capacity due to surrounding wastewater infrastructure constraints. Constructed in 1997, the seven-pond facility borders the city of Morgan Hill and several unincorporated properties. While the Morgan Hill properties are connected to the municipal sewer, five or six neighboring unincorporated properties rely on aging private septic tanks. During an April 27, 2026, committee meeting, Water Supply Operations Manager Bassam Kassab explained that full recharge operations cause groundwater mounding that risks inundating these septic systems. To comply with Santa Clara County Department of Public Health requirements, the utility must keep the water table at least 23 feet below the surface. This restriction has forced Valley Water to operate only one of the seven ponds at minimal flows, leaving thousands of acre-feet of recharge capacity stranded. To reclaim the lost asset, Valley Water commissioned engineering consultant GAI to conduct an optimization study. The desktop analysis evaluated eight alternatives, narrowing them down to four closely scored options to restore full or partial capacity. The highest-scoring alternative involves Valley Water installing new, alternative wastewater treatment systems at the affected properties that would not be impacted by a higher water table. Kassab noted that if homeowners refuse the upgrades, the district could consider eminent domain following further planning and design. Tying for second place were options to connect the properties directly to Morgan Hill's sewer system—which would require approval from the Local Agency Formation Commission (LAFCO)—or permanently operating the ponds at a lowered capacity. The final shortlisted option is to acquire the properties outright. Under this scenario, the district could purchase the multi-million-dollar homes, upgrade the septic systems, and resell them to recoup costs. The San Pedro Ponds optimization is one of four South County recharge improvements outlined in Valley Water's Water Supply Master Plan, which the board approved in November 2025. The committee will continue to review the alternatives before advancing a preferred capital project to the full board for planning and design.