The San Diego County Treasurer-Tax Collector's East County Branch in Santee operates from the 25,000-square-foot county services building at 10144 Mission Gorge Road, accepting secured, unsecured, defaulted, supplemental, and escape property tax payments. The Santee branch is one of four county locations — alongside the downtown San Diego, Chula Vista, and San Marcos offices — and is the only East County site where taxpayers can submit payments in person, including cash, with a payment dropbox available outside the building for after-hours deposits, with tax preparation support available from East County firms such as Mineo & Associates on Cuyamaca Street. San Diego County property tax collections generate over $9 billion annually across approximately 980,000 parcels, with the City of Santee's assessed valuation reaching $9.29 billion in 2024 — a 5.42 percent increase from the prior year. The office shares the Mission Gorge Road facility with the County Assessor/Recorder/County Clerk's East County Branch, consolidating property-assessment, recording, and tax-payment functions at a single location. Taxpayers filing annual returns or managing installment schedules also work with walk-in tax preparation offices including Jackson Hewitt Tax Service at Santee Town Center on Town Center Parkway. The branch processes the two annual installment deadlines — first installment delinquent after December 10 and second installment delinquent after April 10 — with e-check payment available at no fee through the county's online portal.