J-51 Tax Exemption/Abatement

J-51 provided tax benefits for renovating residential buildings, including major capital improvements and conversions of non-residential buildings to residential use — both a tax exemption (reducing assessed value) and a tax abatement (direct reduction in tax bill). The legacy program lapsed in 2022; a revamped version, the Affordable Housing Rehabilitation Program (informally "J-51 R"), was enacted in 2024 with tighter affordability requirements. Many buildings still carry active legacy J-51 benefits that phase out over time.

Like 421-a, J-51 triggers rent stabilization requirements for buildings with 6+ units. Understanding J-51 status is important for investors evaluating multifamily properties.