Property taxes in Sullivan County, New York come from three places at once: the county, your town, and your school district. County and town taxes are billed together in January, school taxes arrive in early September, and the Sullivan County Treasurer handles collection once bills go unpaid. The fastest ways to lower what you owe are the STAR school tax credit, veterans and senior exemptions, and challenging your assessment on Grievance Day in May.
What Makes Up Your Bill
Three separate charges land on your property. The county portion funds regional services like roads and emergency response. The town portion covers your municipality’s highway department, code enforcement, and administration. The school district portion is usually the largest line.
Each town’s assessor sets the assessed value of your parcel, and because towns assess at different percentages of market value, New York applies equalization rates so no municipality carries a disproportionate share of county or school taxes.1New York State Department of Taxation and Finance. Equalization Rates If your assessment feels off, that number is where to push back.
Deadlines and Penalties
County and town taxes can be paid without penalty through January 31. Interest starts in February at 1%, climbs to 2% in March, and a $2 second-notice fee is added that month. Anything still unpaid after March 31 is turned over to the Sullivan County Treasurer.2Town of Thompson. Tax Collector
School tax bills go out in early September with the due date printed on the bill. Unpaid school taxes are turned over to the county after November 15 and re-levied on the following year’s property tax bill with an additional penalty.2Town of Thompson. Tax Collector
If your taxes have become seriously delinquent and are already with the county, you may be able to negotiate an installment agreement. The county charges 12% annual interest on the remaining balance, and any installment received more than 15 days late triggers a 5% late charge on top of that.3Sullivan County NY. Tax Installment Agreements
How to Pay
Sullivan County does not accept online property tax payments. You have three options:4Sullivan County NY. Property Taxes
- By mail. Send a check or money order payable to “Sullivan County Treasurer” to PO Box 5012, Monticello, NY 12701.
- In person. Visit the Treasurer’s Office on the first floor of the Government Center at 100 North Street in Monticello.
- By credit card. Call the Treasurer’s Office to pay by phone. MasterCard, Visa, and Discover are accepted, with a 2.75% convenience fee charged by the bank.
Before the March 31 turnover, local town tax collectors sometimes offer additional methods, including online credit card or ACH payments with their own processing fees.2Town of Thompson. Tax Collector Check with your town for what’s available where you live.
STAR School Tax Relief
STAR reduces school taxes, and how you receive it depends on when you first enrolled. New homeowners register for the STAR credit through the state, which sends a check or direct deposit you apply toward your school bill.5New York State Department of Taxation and Finance. STAR Resource Center If you’ve received the STAR exemption continuously since 2015 at the same primary residence, you can keep it on your bill.
Basic STAR
Basic STAR is available to all primary-residence homeowners. The income ceiling is $500,000 for the STAR credit and $250,000 for the legacy exemption.6New York State Department of Taxation and Finance. STAR Eligibility Eligibility for the 2026 benefit is based on your 2024 federal or state return.
Enhanced STAR
Enhanced STAR gives seniors a larger benefit. All owners must be 65 or older, and combined income of owners and resident spouses cannot exceed $110,750 for the 2026–2027 school year.7New York State Department of Taxation and Finance. Types of STAR That ceiling adjusts annually with a cost-of-living formula.
Register for STAR through the New York State Department of Taxation and Finance, not your local assessor. You’ll need proof of primary residence, such as a driver’s license, voter registration, or vehicle registration.6New York State Department of Taxation and Finance. STAR Eligibility The older application forms (RP-425-E and RP-425-IVP) have been discontinued along with new exemption enrollment.8New York State Department of Taxation and Finance. STAR Exemption Forms
Veterans and Senior Exemptions
Alternative Veterans Exemption
The alternative veterans exemption reduces assessed value by 15% for wartime service, with an additional 10% for service in a combat zone or receipt of an expeditionary medal. Veterans with service-connected disabilities receive a further reduction equal to half their disability rating.9New York State Department of Taxation and Finance. Alternative Veterans Exemption Each taxing jurisdiction sets maximum dollar limits, so actual savings vary by town and school district. The property must be your primary residence.
Senior Citizen Exemption
Separate from Enhanced STAR, Sullivan County offers a senior exemption under local law. Homeowners age 65 and older with annual income at or below $20,500 can receive up to a 50% reduction in assessed value for county tax purposes.10eCode360. Part 4 Senior Citizen Tax Exemption Individual towns and school districts may adopt their own versions with different income limits, so ask your local assessor what applies to each piece of your bill. Eligible seniors can claim this exemption and STAR together.
Challenging Your Assessment
If you think your assessed value is too high, you get two shots at it. First is informal: call or visit your town assessor with recent comparable sales, an independent appraisal, or documentation of property defects before Grievance Day. Many disputes get resolved at this stage.
If that doesn’t work, file Form RP-524 with your town’s Board of Assessment Review on Grievance Day. For most Sullivan County towns that falls on the fourth Tuesday in May, which is May 26, 2026.11New York State Department of Taxation and Finance. RPTL Section 512 – Alternate Grievance Days Some municipalities set different dates by local law, so confirm with your assessor. The form must be received by the deadline, not just postmarked.
If the Board rules against you, the next step is a Small Claims Assessment Review (SCAR) petition. The filing fee is $30, and the case is heard by a specially trained hearing officer rather than a judge. SCAR is available to owner-occupants of one-, two-, or three-family homes. A professional appraisal to support your case typically runs a few hundred dollars for a standard residential property, more for complex or high-value homes.
What Happens If You Don’t Pay
When taxes stay unpaid long enough, the county can take the property through in rem foreclosure under New York Real Property Tax Law Article 11.12Justia. New York Real Property Tax Law Article 11 – Procedures for Enforcement of Collection of Delinquent Taxes The county files a petition in court, and a redemption period follows during which you can still save the property by paying all back taxes, interest, and penalties. Notices go out by certified mail and ordinary first-class mail, with additional address searches and physical posting on the property if mail is returned undelivered within 45 days.
If the redemption period runs out, title transfers to the county and the property is scheduled for a public auction, held online in recent years over several days in September.13Sullivan County NY. Tax Foreclosure Auction Set for September 15-17 Sales are subject to approval by the Sullivan County Legislature, and once finalized, the original owner’s rights are permanently extinguished. If you’re falling behind, call the Treasurer’s Office about an installment agreement before the foreclosure clock starts; costs only grow from there.