Mendocino assessor reports Williamson Act corrections, vendor issues; supplemental notices add about $27.8 million assessed value

Katrina Bartlemais, Mendocino County Assessor and County Clerk‑Recorder‑Registrar of Voters, updated the Board of Supervisors on the office’s ongoing work to correct Williamson Act assessments and to process supplemental assessment notices.

Bartlemais said the office has pulled staff from routine duties to advance the Williamson Act recovery project and is now in validation and testing. "We are about 80% complete with our Williamson Act project," she said, but added the county has discovered a vendor‑system issue affecting some parcels: in certain cases the program is doubling — not adding — the recovery value for parcels with prior escape or correction filings. She said the vendor’s engineers are working on the problem and the assessor’s office expects to meet an April 18 deadline; parcels with unresolved issues will be held out for separate processing.

Bartlemais reported recent supplemental notice activity: appraisers completed 258 supplemental notices for changes in ownership and new construction in February contributing $22,000,000 in assessed value, and 18 supplemental notices in March bringing $5,800,000 — a combined total of $27,800,000 in assessed value to the roll. She noted those figures reflect total assessed value, not prorated tax revenue, and that the auditor’s office will calculate tax effects once the assessor’s data are finalized and transmitted.

The clerk‑recorder e‑recording rollout is delayed pending vendor fixes, Bartlemais said. She urged taxpayers who receive escape or supplemental notices and do not understand them to call the assessor’s office for an explanation or to arrange payment plans through the tax collector.

Supervisors asked clarifying questions about timelines and impacts to the auditor and tax collector. Supervisor Klein asked what taxpayers should do when they receive notices; Bartlemais recommended they contact the assessor’s office and noted state law allows assessment changes back up to four years. Supervisor Williams confirmed the assessor expects to have roll corrections ready by the April 18 deadline so the auditor controller’s office can process them.

Why it matters: the corrections and supplementals affect the secured property tax roll; the assessor’s work could increase assessed values and generate additional tax assessments once allocations and proration are determined by the auditor’s office.

The board thanked staff for the work and Bartlett said the office will continue to coordinate with IT and the auditor controller.