Westchester Renovation Permits & Code: The 2026 Complete Guide
A practical 2026 guide to Westchester renovation permits and code requirements — the building permit, architectural review, wetlands and steep-slope rules, septic capacity, FEMA flood compliance, and town-by-town review timelines. Links to deeper guides for every Westchester city, town, and village we've covered.
Adding a Primary Suite in Armonk: Lot Coverage, Septic, and the 6-Month Permit Reality
Primary suite additions are one of the most common Armonk renovations, but the regulatory reality stacks lot coverage compliance, county-level septic capacity review, and frequently wetlands or slope review on top of standard building permits. This guide walks through the 6-month pre-construction calendar, the $385K–$625K typical project budget plus septic upgrade costs, and the strategic design moves that compress the timeline.
Septic Capacity in Northern Westchester: When Adding a Bedroom Triggers a System Upgrade
New York State sizes residential septic systems by bedroom count — 150 gallons per bedroom per day — which means most northern Westchester additions that add a bedroom trigger Westchester County Department of Health review of the existing system's capacity. This guide walks through how the bedroom-count rule actually works, what an upgrade costs across gravity and engineered system options, and how to design the project to either avoid the trigger or sequence the upgrade strategically.