Union County, NJ Property Tax Appeal Guide for 2027

What deadline matters first

For most Union County homeowners, the first deadline for a regular 2027 assessment appeal is April 1, 2027. If your municipality implements a municipal-wide revaluation or reassessment for 2027, the regular deadline is May 1, 2027 instead. Union County also follows the rule that 45 days from the bulk mailing of the Notice of Assessment controls if that gives a later date, according to the Union County Board of Taxation Tax Appeal Filing Packet.

The official appeal body is the Union County Board of Taxation. Online filing is allowed until 11:59:59 p.m. local time on the applicable deadline. Paper appeals must be physically in the Board office by close of business, and Union County states that postmarked mail is not enough if it arrives late.

For a sense of filing volume, New Jersey’s 2025 county tax board summary lists an appeal count of 820 total Union County property tax appeals, including 336 residential appeals. That means the Board regularly handles this kind of filing, even though each property is decided on its own evidence in the State of New Jersey Summary of Property Tax Appeals - 2025.

Union County’s approximate countywide weighted 2025 effective tax rate estimate for this policy is 2.07%. Treat that as a planning estimate only. The New Jersey Division of Taxation explains that an effective tax rate is a statistical comparison tool and is not the rate used to compute a particular property’s bill, as shown in the state’s local property tax statistical information.

The common value appeal

The most common homeowner filing reason is Valuation / Assessment Unreasonable, Excessive, or Discriminatory. In plain English, you are saying the assessment is too high when tested against your home’s true market value as of October 1, 2026, which is the pretax assessment date for the 2027 tax year.

Union County explains that the current assessment is presumed correct. That means the burden is on you, the petitioner, to prove the assessment should change. The Board is not starting from the idea that the assessment is wrong.

For most non-revaluation municipalities, New Jersey’s Chapter 123 test matters. Chapter 123 uses the municipality’s annual common-level ratio and a 15% range to compare proven market value with the assessment. If your town has just implemented a revaluation for the appeal year, Union County says Chapter 123 does not apply because the new assessment is treated as market value.

Other reasons you might appeal

Classification means you believe the property is assigned to the wrong New Jersey property class. This is not the same as saying the market value is too high. For example, the issue might be whether the property was classified as the wrong type of property.

Denial of Deduction means you are challenging the denial of a statutory deduction, such as an available senior citizen, disabled person, veteran, or surviving-spouse deduction. This is about eligibility for a deduction, not about proving a lower market value with comparable sales.

Added/Omitted Assessment means you are contesting an added assessment or omitted assessment. These often arise when property was added to, improved, or left off the tax list and later corrected. This follows a separate added or omitted assessment process and calendar, not the regular April 1 valuation cycle.

If your Notice of Assessment says something else changed

A Notice of Assessment is the notice that tells you the assessed value placed on your property for the tax year. Union County’s packet also uses the official term Notification of Assessment for the bulk-mailed notice, and Notification of Change of Assessment when a changed assessment is issued.

If you receive a changed assessment notice, do not assume the ordinary April 1 date is the only date to check. New Jersey filing instructions say a taxpayer has 45 days to file upon issuance of a Notification of Change of Assessment, and separate 45-day rules can apply after the bulk mailing of the assessment notice.

This is one of the easiest places to lose rights by waiting. Save the envelope, notice, and mailing date if you have them. If your town is in a municipal-wide revaluation or reassessment, confirm whether the May 1 rule applies for the 2027 appeal year.

What evidence helps

Union County comparable-sale evidence should focus on recent, usable, arm’s-length sales. For the 2027 regular appeal year, this policy uses sales from July 1, 2025 through October 1, 2026. Arm’s-length means a normal willing buyer and willing seller, without unusual pressure or special circumstances.

Submit no fewer than 3 and no more than 5 comparable sales. Union County’s instructions say comparable-sale information should include the block, lot, sale price, and deed date, and that not more than five comparable sales may be submitted. If the sales are not included with the petition, serve them on the County Board, municipal assessor, and municipal clerk no later than seven calendar days before the hearing.

Look for sales that are similar in neighborhood or location, property type, living area, lot size or acreage, zoning and use, age, style, and condition. Union County does not publish a fixed distance or square-footage tolerance, so TaxSauce uses a conservative 1-mile search radius while still prioritizing actual similarity.

Do not rely on other homes’ assessments or tax amounts as proof of value. Union County’s instructions state that comparable sales are acceptable evidence of market value, while comparable assessments are unacceptable. SR-1A sale records should be checked for usability, especially for sales involving foreclosure, bankruptcy, related parties, or other non-arm’s-length concerns.

You may use an appraisal, but it comes with formal hearing requirements. Union County’s instructions say that if an appraisal is used as evidence, the appraiser must appear to testify, and the written report must be served as required.

What the board can and cannot decide

The Union County Board of Taxation can decide whether your assessment should be changed. It can consider your evidence, the municipality’s position, Chapter 123 where it applies, and the rules for the filing reason you selected.

The Board cannot lower school budgets, municipal budgets, county budgets, or tax rates. Union County’s instructions are clear that only the property value can be appealed, not the amount of taxes on the property. A changed assessment may affect the bill, but the appeal itself is about assessment value.

You also need to keep paying required taxes and municipal charges. Union County’s filing instructions cite the rule that a taxpayer filing an assessment appeal must pay taxes and municipal charges due through the first quarter, unless the payment requirement is relaxed.

If you disagree with the county board judgment, a further complaint may be filed with the Tax Court of New Jersey within 45 days from service of the judgment. Properties assessed over $1,000,000 may have additional direct Tax Court filing options under the official instructions.

How TaxSauce helps

TaxSauce helps you slow the process down and look at the facts in order. We help read your notice, identify the relevant deadline, estimate whether recent usable sales support a lower assessment, and organize the evidence a homeowner would want to review before deciding what to submit.

For a Valuation / Assessment Unreasonable, Excessive, or Discriminatory filing, TaxSauce can help build a comparable-sales packet using the Union County rules above. That includes focusing on sale dates, similarity, sale usability, and the information the Board expects to see.

TaxSauce can also help flag when your issue may be Classification, Denial of Deduction, or Added/Omitted Assessment instead of a value dispute. Those issues need different facts than a comparable-sales value filing.

You remain in control. You review the materials, choose what to use, and decide whether to file online, file on paper, seek professional advice, or take no action. TaxSauce does not guarantee that the Board will accept every comparable, change the assessment, or reduce the tax bill.