Sullivan County property tax appeals
Your deadline runs from the date on your assessment notice.
Appeals go to Sullivan County Board of Assessment Review.
New York assesses your home at a percentage of its market value, and you can grieve the assessment if it is too high. Most towns hear challenges on Grievance Day, the fourth Tuesday in May, while New York City and Nassau County run their own winter windows. An appeal makes sense when recent comparable sales show your value is too high; it usually will not help if your bill rose only because the tax rate went up.
- Recent comparable sales show your home's market value, times your community's assessment ratio, is below your assessment.
- You bought recently for clearly less than the market value your assessment implies.
- Your town assesses at a low ratio, which can magnify even a small over-assessment.
- Your bill went up but your assessment is fair. A higher bill often comes from the tax rate or the budget, not the value.
- You just think your taxes are too high, with no evidence the assessed value is wrong. The board reviews value, not the size of the bill.
Read the full explanation
In New York, your assessor estimates your home's market value, and outside New York City and Nassau County that value is assessed at a uniform percentage of market value each year. You compare your assessment to your home's market value times that percentage, and you can grieve it if it is too high, or challenge a wrong classification or a denied exemption. In most communities you file Form RP-524 by Grievance Day, the fourth Tuesday in May, with your local Board of Assessment Review. New York City uses the City Tax Commission with a March deadline set by the City Charter, and Nassau County uses its own Assessment Review Commission on a winter window. An appeal helps when recent comparable sales show your market value, times the local assessment ratio, is below your assessment. It usually will not help just because your tax bill went up, since a higher bill can come from the tax rate or the budget, not your assessment. This is general information, not tax advice.
Source: New York State Department of Taxation and Finance (fair assessments) · checked 2026-07-16. In Florida we run the numbers for you. In New York we give you the deadline, where to file, and the rules, verified against official sources.
- Filing window:
- File Form RP-524 with the county Board of Assessment Review by the Grievance Day set for your assessing unit. Local dates vary, so confirm the date printed by your assessor. After the board, eligible homeowners may use Small Claims Assessment Review, while other court review proceeds under Article 7.
- Where to file:
- Sullivan County Board of Assessment Review
Verified against official sources, approved 2026-08-08.
In most New York communities, Grievance Day, the deadline to file a complaint on your assessment with the Board of Assessment Review, is the fourth Tuesday in May. Some assessing units set their own date, so confirm yours with your assessor.
Source: official schedule · checked 2026-07-14. We update exact dates when the official schedule is published.