Planning commission approves coastal permits for two test wells near Pescadero

The San Mateo County Planning Commission on Dec. 10 approved a set of permits allowing two new test-well locations on three parcels just west of Cabrillo Highway in Pescadero (county file PLN202500081) after staff presented environmental mitigation conditions and a prior CEQA addendum.

Planner Kanoa Kelly told commissioners the parcels are near wetland and marsh areas with identified special-status plants and that an IS/MND circulated in 2023 had been certified; staff prepared an addendum concluding no new substantial changes or mitigation were required for the two new locations and recommended approval subject to conditions in Attachment A.

Evan Wolf, a geologist for Water Solutions, described the site's prior drilling history: of three earlier boreholes, one was dry, one produced about three-quarters of a gallon per minute and one produced about 1.4 gallons per minute. "That doesn't meet the 2 and a half gallons a minute required by the county for a residential development," Wolf said, noting the team saw increasing yields across attempts and that geophysical tests for the two proposed spots indicate water presence but cannot guarantee yield.

Wolf explained the groundwater comes from a deep fractured sandstone formation; success depends on intersecting fractures at the borehole. He said salinity testing showed total dissolved solids well below seawater levels ("probably on the order of 1,000 or less"), and the wellheads would sit above local grade on a site roughly 40 feet above sea level.

Commissioners raised questions about whether multiple previous wells could be combined to meet county standards and the rules on retaining earlier wells. Staff and the applicant's representative agreed to confirm permitting rules with Environmental Health; staff noted county requirements typically allow permitting a single well for a residence and that previously drilled, nonpermitted holes may need to be decommissioned.

The commission also asked about biological protections identified by the project biologist. Staff said mitigation measures (including seasonal work windows and on-site monitoring by a certified biologist contracted to the biologist who prepared the report) will be conditions of approval.

After public input (a Zoom speaker raised an audio/accessibility concern), a motion to approve the coastal development permit, PAD permit and architectural review was seconded and carried unanimously.

The permit approval includes the conditions listed in Attachment A and staff follow-up to confirm final details with Environmental Health about existing wells and any required decommissioning. No construction activities subject to the biological timing restrictions may proceed until those conditions are satisfied.