"Petitions must be filed and received by May 1st." That single line, buried in the instructions on New Jersey's property tax appeal form, describes what happens to most of Somerset County every year, even though most people searching for the state's appeal deadline land on a different date entirely: April 1.
Search "New Jersey property tax appeal deadline" and April 1 is what comes back, over and over, because it's the standard rule for the vast majority of the state's 564 municipalities. But Somerset County isn't running on the standard rule this cycle. According to the county's own Board of Taxation, only five of the county's 21 municipalities, Montgomery Township, North Plainfield Borough, Raritan Borough, Somerville Borough, and South Bound Brook Borough, filed under the April 1 deadline for the 2026 tax year. The other sixteen, including Bridgewater, Franklin, Hillsborough, and Bernards, were on a May 1 schedule because each of them was mid-revaluation or reassessment.
That's not a rounding error. It means the "exception" clause in New Jersey's appeal statute, the one that exists for towns undergoing a formal revaluation, was actually the majority condition in Somerset County this year. If you're selling a house in Bridgewater, buying one in Hillsborough, or comparing two towns you've never lived in before, the deadline you assume applies is more likely wrong than right.
The Two Tracks, and Who's on Each One
New Jersey law sets two possible appeal deadlines. Under ordinary conditions, a property owner must file a petition with the county board of taxation by April 1 of the tax year, or 45 days after the municipality mails its bulk assessment notices, whichever is later. But where a town has just completed a municipal-wide revaluation or reassessment, the law gives owners an extra month: petitions in those towns are due May 1.
For the 2026 tax year, Somerset County's own tax board lays out exactly which track each municipality is on:
| April 1 deadline | May 1 deadline (revaluation/reassessment) |
|---|---|
| Montgomery Township | Bedminster Township |
| North Plainfield Borough | Bernards Township |
| Raritan Borough | Bernardsville Borough |
| Somerville Borough | Bound Brook Borough |
| South Bound Brook Borough | Branchburg Township |
| Bridgewater Township | |
| Far Hills Borough | |
| Franklin Township | |
| Green Brook Township | |
| Hillsborough Township | |
| Manville Borough | |
| Millstone Borough | |
| Peapack-Gladstone Borough | |
| Rocky Hill Borough | |
| Warren Township | |
| Watchung Borough |
Sixteen towns on one side, five on the other. This list resets every year as different municipalities move through their own revaluation and reassessment cycles, so the specific names on each side will shift over time. What won't shift is the mechanism itself: whichever track a given town lands on in a given year, the deadline moves with it, and nothing about a home's price range or school district tells you which track applies.
Why the Extra Month Exists
A revaluation or reassessment isn't a routine tax bill update. It's a wholesale re-pricing of every taxable property in a municipality, conducted to correct for years of drift between what a house is assessed at and what it would actually sell for. Homeowners in a reval town open a February notice and, for the first time in years, see a number that may have moved by tens of thousands of dollars in either direction.
New Jersey's extra month for these towns exists because that notice arrives with far less warning than a routine annual adjustment. Somerset County property owners receive assessment notices around the beginning of February each year, and the Hillsborough Township assessor's office, along with several other Somerset municipalities, encourages owners who disagree with a new number to talk to the assessor's office directly before filing anything formal. In a reval year, that conversation carries more weight, because the assessor's office has fresh comparable sales data behind the new figure and can walk through exactly how it was built.
The Number That Actually Decides an Appeal
Here's where most people misjudge their own case. The instinct is to compare your assessed value to what you think your house would sell for today and file if the gap looks big enough. That's not how a Somerset County appeal is actually decided.
New Jersey uses something called the Chapter 123 ratio, sometimes called the Director's ratio or the common level range, which represents the average relationship between assessed value and true market value across an entire municipality. When you file an appeal, your assessed value isn't measured against raw market value. It's measured against your home's market value multiplied by that ratio. If a town's ratio has drifted to, say, 85 percent, and your home is genuinely worth $400,000, the correct assessment under Chapter 123 is closer to $340,000, not $400,000. An assessment sitting at $380,000 would be excessive under that standard even though it looks reasonable against the raw sale price.
This is the number a New Jersey appeal actually turns on, and it's published annually by the state for every county, including Somerset. A seller or buyer who skips this step and argues from raw market value alone is arguing the wrong case, no matter how strong their comparable sales look.
What This Means If You're Closing in Somerset County This Fall
If you're listing a home in one of the sixteen reval-track towns, the assessed value on file right now reflects a number that was freshly built this year, using sales data gathered up to the town's October 1 valuation date. That number is likely closer to true market value than it would be in a town that hasn't been revalued in a decade, which matters when a buyer's agent or appraiser starts asking why your tax bill looks the way it does.
If you're buying in one of the five April 1 towns, ask when that municipality last completed a full revaluation. An assessment that's ten or fifteen years old can sit well below current market value, which keeps the tax bill artificially low for now, but it also means a future revaluation could reset that number sharply upward, and buyers should factor that possibility into a long-term ownership budget rather than assuming today's tax bill is a stable baseline.
Either way, a successful appeal judgment in New Jersey typically holds for the year it's filed plus the two following years under the state's Freeze Act, unless the town undergoes a revaluation in the meantime, in which case the freeze ends and the new numbers take over. And an appeal can't be filed at all if the current or prior year's property taxes are in arrears, which matters for any transaction where back taxes are part of the negotiation.
What the Tax Bill Actually Buys, Town to Town
The dual-deadline system exists because Somerset County's 21 municipalities don't move in sync, and neither do their tax bills. Based on 2025 figures, Bedminster Township carried the county's lowest average tax bill at roughly $5,806, while Watchung Borough carried the highest at roughly $18,279. Both are on the May 1 track this cycle. Both sit in the same county. The difference has nothing to do with which deadline applies and everything to do with local budgets, school funding formulas, and how recently each town's ratable base was last brought current.
For a buyer comparing two similarly priced homes in different Somerset County towns, that spread is real money over a decade of ownership, and it's a more useful comparison than a headline county-wide average, which tends to flatten towns that don't actually resemble each other.
A Few Questions Worth Asking Before You File
Does the deadline reset every year, or is it fixed to my address? It resets. A town's track depends on whether it's undergoing a revaluation or reassessment in that specific tax year, so a town on the April 1 schedule this year could shift to May 1 in a future reval cycle. Check the current year's list with the Somerset County Board of Taxation before assuming last year's deadline still applies.
If I win an appeal right before selling, does the buyer inherit the lower assessment? Generally yes, under the Freeze Act, for the remainder of the freeze period, unless the town completes a revaluation in the meantime. That's worth mentioning in any conversation with a buyer's agent or attorney.
Can I appeal after closing if I think I overpaid based on the assessment? Yes, a new owner can file in their own name for a future tax year, following the same April 1 or May 1 rule that applies to their specific municipality that year.
The county publishes its full equalization tables and appeal schedule on the Somerset County Board of Taxation's page, and the state's underlying rule is spelled out directly on the New Jersey Division of Taxation's assessment and appeals page. Both are worth five minutes before you assume you know your own deadline.
If you're weighing a purchase or a listing in Somerset County and want help reading what a specific town's assessment history actually says about your numbers, Cheryl Brunetti can walk through it with you before you file anything.