Across 252 permits filed since 2025-01-25, the median is $12,250; half of projects fall between $5,000 and $50,000. Figures are permit valuations reported to building departments. National cost guides answer this question with averages from other markets; these numbers are what homeowners in Westchester County, NY actually reported when they pulled permits.
Recent filings
- Electrical wiring in newly renovated basement (outlets, switches, lights) and HVAC equipment.White Plains · 2026-07-23$12,000
- Legalization of the basement HVAC Unit installation.Village of Ossining · 2026-07-23$5,000
- Finished Basement - Installation of single pole switches, 3 way switches, outlets, recessed lights, 2 foot strip lights, outside wall sconce, smoke/carbon monoxide alarms, washing machine outlet, install make-up air fan, wire AC compressor,Village of Ossining · 2026-07-23$10,000
How to read these numbers
Permit valuations are the project cost the applicant reports to the building department. They skew slightly low — nobody rounds up for the permit fee — and scope varies, so the middle-half range is the honest picture: half of all basement finishing permits in Westchester County, NY came in between $5,000 and $50,000. We exclude permits under $1,000, jobs filed as whole-house construction, and counties whose building departments don't reliably report valuations.
Same project, other places
Basement finishing in New YorkBasement finishing in ConnecticutBasement finishing on Long Island