Nassau County, NY — Property Tax Underwriting Guide
New York · Annual market review
What this means for multifamily underwriting
Nassau is among the highest-taxed counties in the US. Combined effective rates (county + town + school district) on multifamily routinely exceed 2.5%. Verify the school district overlay for the subject parcel.
Transaction type breakdown
Nassau assesses annually at full market value. Recent sale prices are strong evidence of value and commonly influence the next assessment cycle.
Refinance does not affect assessed value.
Ownership change is market evidence and can influence the next assessment cycle.
Tax appeal information
Combined rate varies significantly by incorporated village and school district. The 25.0 placeholder is a mid-county estimate; high-rate school districts can run 30-35+ per $1,000.
Guide review
County guidance last reviewed: June 15, 2026
Tax-rate scope: County-level underwriting placeholder; not a parcel-specific tax rate.
Official sources: Nassau ARC (appeals)
Annual-market model is well established for Nassau; millage is a mid-county placeholder pending school district overlay verification. | REVIEW REQUIRED: estimator-critical numeric fields (assessment_ratio, effective_millage) are analyst mid-county placeholders, not source-verified per-county — do not re-enable estimator_enabled until they are confirmed against a primary source (assessor/treasurer site or NYS ORPTS Municipal Data Portal) and last_verified is updated accordingly.
Parclio estimates are underwriting guidance, not legal or tax advice. Always verify millage rates, the seller's assessed value, and appeal deadlines with the county assessor or local counsel before relying on these numbers for a credit decision.
Run a tax reset estimate for Nassau County
Use Parclio's estimator to model the post-closing tax bill, NOI impact, DSCR change, and underwriting memo language for your next Nassau County deal.