Showing ordinances that apply to Mount Sinai, NY
Mount Sinai is an unincorporated community (population 11,623) in Suffolk County, New York. Because Mount Sinai is not an incorporated city, it does not have its own municipal code. Instead, Suffolk County ordinances apply directly to properties here. The adu rules rules below are the ones that govern your area.
Accessory apartments (ADUs) are legal in every Suffolk County town under varying rules. Most towns require owner-occupancy of the primary dwelling, a minimum lot size (often 7,500-20,000 sq ft), a rental permit, and one off-street parking space for the ADU. Internal conversions and attached ADUs are most commonly permitted; detached ADUs are more restricted.
Brookhaven Town Code Chapter 85 allows one accessory apartment per single-family home with owner-occupancy, 300-650 sq ft ADU size, and biennial permit renewal. Islip Chapter 68-20 permits accessory apartments with similar conditions. Huntington, Smithtown, Babylon, and the East End towns have their own programs. Suffolk County Department of Health Services must approve any ADU on septic for added flow capacity, including the new I/A OWTS (nitrogen-reducing) systems required in many areas. New York has not adopted a statewide ADU preemption law.
Illegal accessory apartment: $500-$2,500 first offense, up to $10,000 repeat, plus rent-disgorgement orders. Unpermitted septic increase: Suffolk DHS stop-use order.
See how Mount Sinai's adu rules rules stack up against other locations.
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