Two Union County listings can show tax rates that look nothing alike and still cost their owners almost the same amount every year. The reverse is just as common: two towns with rates that appear close on paper can carry meaningfully different real burdens. The number printed on a listing sheet or a portal search filter is not the number that determines what you'll actually pay. The number that matters is buried in a state certification most buyers never open, and in Union County right now, that certification tells a story worth understanding before you make an offer.
Nineteen of the county's twenty-one municipalities are currently running on property assessment rolls the state considers materially out of date. That is not a rounding error or a temporary blip. It is the current, published condition of the market you are shopping in, and it changes how you should read every tax line on every listing from Westfield to Rahway.
The Two Rates On Every Union County Listing
New Jersey law requires every parcel to be assessed at 100 percent of its true market value. In practice, towns reassess infrequently, home prices keep moving, and the gap between what a house is assessed at and what it would actually sell for widens every year a town goes without a full revaluation. The state tracks that gap with a number called the Director's Ratio, also known as the equalization ratio, and the New Jersey Division of Taxation publishes it annually for every municipality in the state.
The 2026 certification, originally issued October 1, 2025 and amended by the New Jersey Tax Court on January 30, 2026, shows just how wide that gap has gotten in Union County. Nineteen of the county's twenty-one towns sit below the state's 85 percent compliance threshold. Twelve sit below 35 percent. Five sit below 25 percent.
The specifics vary sharply by town. Union Township's ratio is 8.89 percent. Scotch Plains sits at 15.65 percent. Hillside is at 24.33 percent, Linden at 24.64 percent, Plainfield at 24.85 percent, and Cranford at 26.04 percent. Move up the price ladder and the picture shifts but doesn't disappear: New Providence sits at 34.32 percent, Berkeley Heights at 35.73 percent, Summit at 30.81 percent. Mountainside and Westfield are closer to compliant, at 71.29 percent and 72.48 percent. Clark is at 80.01 percent, Fanwood at 65.63 percent, and Elizabeth, the county's largest municipality, sits at 92.76 percent, one of the few towns actually inside the compliant range.
None of this means anyone is being cheated or getting a secret discount. It means the assessed value on a Union County tax card and the price a home would fetch on the open market are, in most of the county's towns, two very different numbers.
Why the Sticker Rate Lies
That gap is exactly why comparing the "general tax rate" printed on a listing, the dollar figure per $100 of assessed value, tells you almost nothing about which town actually costs more to own a home in. A buyer scanning nominal rates alone would see Westfield's general rate near 2.292 and Scotch Plains' near 12.350 and conclude Scotch Plains costs more than five times as much. It doesn't. Once each town's rate is equalized against its own ratio to true market value, the real, comparable burden lands at 1.810 percent in Westfield and 2.137 percent in Scotch Plains, a gap of roughly a third of a percentage point.
On a $1 million home, that translates to about $18,100 a year in Westfield versus $21,370 in Scotch Plains, a real difference worth knowing, but nowhere near the multiple the sticker rates implied.
The same pattern holds across the rest of the county's higher-priced towns:
| Town | 2026 Director's Ratio | Effective Tax Rate |
|---|---|---|
| Westfield | 72.48% | 1.810% |
| Mountainside | 71.29% | 1.566% |
| Summit | 30.81% | 1.475% |
| Berkeley Heights | 35.73% | 1.820% |
| Cranford | 26.04% | 2.106% |
| Scotch Plains | 15.65% | 2.137% |
The effective tax rate, the total levy divided by the property's true market value, is the only figure the state's own data supports comparing across town lines. Cranford's effective rate of 2.106 percent and Westfield's 1.810 percent produce a roughly $2,960 annual gap on a $1 million home, not the six-to-one spread their published Director's Ratios might suggest if read carelessly.
What Happens When a Ratio Finally Breaks: New Providence's Live Case
A Director's Ratio well below 85 percent doesn't sit there forever. At some point the Union County Board of Taxation orders a full revaluation, and New Providence is currently living through exactly that process, which makes it the clearest working example of what a Union County buyer should expect if they're shopping in one of the county's other low-ratio towns.
According to the borough's own Tax Assessor's office, it has been almost twenty-seven years since New Providence last completed a revaluation. Its current equalization ratio is 34.32 percent, meaning the average home on the assessment roll is carried at roughly a third of what it would actually sell for today. A lot can change in a town over twenty-seven years of new construction, renovation, and turnover, none of which gets reflected on an assessment roll until a reval catches up to it.
The borough contracted with Professional Property Appraisers of Delran to run the full revaluation, and the mechanics are laid out on New Providence's own municipal site:
- PPA appraisers, carrying borough-issued identification, ran field inspections from September 2025 through March 2026.
- Every homeowner receives a proposed new assessment once PPA completes its valuation work.
- An informal review period opens directly with PPA before anything becomes final.
- Formal appeals go to the Union County Board of Taxation by May 1, 2027, a month later than the county's standard April 1 deadline, since revaluation years carry extra time for homeowners to review the new numbers.
- Homeowners with an assessed value above $1 million have the option to skip the county board entirely and file directly with the New Jersey Tax Court.
- All valuation work is set to wrap by December 2026, with the new figures applying to the 2027 tax year, not this year's bill.
That timeline matters beyond New Providence. It's the same procedural template the Union County Board of Taxation has followed for reval-ordered towns, and it's roughly what a buyer in Scotch Plains, Cranford, or any other low-ratio Union County town should expect if a reval order eventually lands there too.
Reading This as a Buyer, Not a Statistician
None of this is a reason to avoid a low-ratio town. It's a reason to ask a different question than the one most buyers ask. Instead of "what's the tax rate," ask for the effective rate, and ask whether the town's ratio is drifting toward reval territory or has already been ordered to revalue.
A low ratio isn't a loophole and nobody in a low-ratio town is quietly underpaying relative to their neighbors. The county already uses that same ratio every year to apportion the shared county tax levy fairly across all twenty-one municipalities. What changes at reval time isn't the total amount a town collects, it's how that amount gets redistributed among individual homes based on current values instead of decades-old ones. New Jersey assessors who have run these processes often describe a rough split once a reval lands: roughly 60 percent of homes see little change, 20 percent see an increase, and 20 percent see a decrease, because the reval corrects for uneven appreciation across a town, not blanket appreciation.
That has a practical edge for both sides of a Union County deal. A recently renovated or newly built home in a low-ratio town may be sitting well below what a reval would eventually assess it at, meaning next year's bill could look very different from this year's, whether you're the buyer inheriting that gap or the seller pricing around it.
Frequently Asked Questions
Does a revaluation always raise my property tax bill? No. A reval resets each home's individual assessed value to current market value, but the town's total tax levy doesn't automatically grow because of it. It's a redistribution of who pays what share, not a guaranteed increase.
Where can I check a town's current Director's Ratio myself? The New Jersey Division of Taxation publishes the Chapter 123 Certification of Average Ratios every year, with a ratio and common level range listed for every municipality in the state, including all twenty-one in Union County.
If a town's ratio is very low, does that mean I'm currently underpaying? No. The county equalizes the shared county tax levy using that same ratio every year, so low-ratio towns aren't getting a discount relative to their neighbors. The ratio describes a timing lag between assessed and market value, not a tax break.
Property tax mechanics rarely make it onto a listing sheet, but they show up on every bill you'll pay for as long as you own the home. If you're weighing Union County towns against each other, or trying to figure out where your specific numbers land before you write an offer, Jonathan Guzman can walk through the effective rate, ratio, and reval timeline for the towns you're actually considering. Request a Private Strategy Consultation to get the real numbers before you compare the wrong ones.
