A data rebuttal · San Mateo County schools

Building homes won't overwhelm Peninsula schools. They're already emptying out.

At nearly every housing meeting on the Peninsula, someone stands up to warn that if new apartment buildings are permitted to be built then local classrooms will be flooded with children.

This argument has slowed or blocked thousands of homes across San Mateo County for years. The enrollment data from the California Department of Education, covering every public school district in the county — shows this is to be false.

100%

of Peninsula districts with meaningful housing production have fewer students today than in 2018

—

students lost across the county's 24 public school districts since peak enrollment

—

average enrollment decline from each district's all-time peak to the current school year

San Mateo County has been losing students since roughly 2015 — before the current wave of housing approvals, before the pandemic, and with no sign of reversal.

The concern driving the schools objection gets the causation exactly backwards: it isn't new housing that shrinks the school-age population. It is the decades-long failure to build housing that has made the Peninsula unaffordable for the young families schools need to stay open.

The test

If housing caused enrollment growth, we'd see it here. We don't.

Each dot is a Peninsula school district, plotted against how many housing units it approved (2021–2025) and how much its enrollment changed since 2018. The schools argument predicts a positive slope — more building, more children. The actual slope is flat to negative. Every district is below zero.

Elementary High school Unified Trend line

The predicted signal is absent. Jurisdictions like Redwood City and South San Francisco — which permitted hundreds of units — show enrollment declines indistinguishable from Hillsborough and Portola Valley, which built almost nothing. Permitting more housing has not sent more children to schools. It has not even slowed the rate of decline.

The backstory

The decline started a decade ago, before any housing wave.

K–12 enrollment indexed to 2018 = 100. The bold line is the county total; lighter lines are individual districts. Most peaked in 2015–2017 — years before any significant Peninsula housing project was approved or occupied. The pandemic deepened the drop. The recovery has been partial and uneven.

County total Individual districts 2018 baseline

Cost is the driver, not construction. At Peninsula prices, young families either can't move here or eventually leave. The school-age population has been contracting for a decade as a direct consequence of housing scarcity. Adding homes — particularly affordable ones — is more likely to slow the enrollment decline than to accelerate it.

The implication

Blocking housing doesn't protect schools. It starves them.

California funds schools through the Local Control Funding Formula, which allocates money per enrolled student. Every child who leaves the system — or never arrives — is funding that cannot pay teachers, maintain facilities, or keep programs running. Peninsula districts are not straining under growth pressure. They are closing classrooms and consolidating schools under the weight of sustained decline.

The families most likely to bring school-age children to the Peninsula are exactly the families who need more affordable options to get here. The schools objection to new housing — repeated at city hall meetings across the county, cited in planning documents, weaponized in CEQA challenges — is not supported by the enrollment record. The data points the other way.