If you own a home on Oahu, or you're closing on one this year, there's a property tax change working its way through Honolulu Hale that's worth your attention. The homeowner exemption, which reduces the assessed value your property taxes are based on, is set to grow in 2027, and the City Council is already debating a second increase on top of that. None of it happens automatically for new owners, and there's a real deadline coming up on September 30. Here's what's actually changing and what to do about it.

What the Exemption Does Right Now

Today, an owner-occupant on Oahu who has filed for the home exemption gets $120,000 knocked off their assessed value if they're under 65, or $160,000 if they're 65 or older by June 30 of the prior tax year. At the flat residential rate of $3.50 per $1,000 of net taxable value, that exemption is the difference between paying tax on your home's full assessed value and paying tax on a meaningfully smaller number. It's one of the few tools Oahu homeowners have to soften rising assessments, and it only applies if you've actually filed the claim form — it isn't automatic just because you live in the house.

The Increase Already on the Books

Last year, the City Council passed ordinances raising those amounts to $140,000 for owners under 65 and $180,000 for owners 65 and older. That increase takes effect for the tax year beginning July 1, 2027. It isn't in your current tax bill, but it's locked in for next year.

A Second Increase Is Now Under Debate

As of this month, the Council is weighing two more bills. Bill 45 would push the under-65 exemption to $160,000, and Bill 46 would push the 65-and-older exemption to $200,000, both aimed at fiscal year 2029. Advocates testifying in favor point out that a $20,000 bump in the exemption saves a homeowner about $70 a year at the current residential rate — modest, but it's meant to keep pace with assessments that have kept climbing faster than the exemption has. Nothing here is finalized, and Council bills can stall or change before a final vote, so treat the 2029 numbers as proposed rather than guaranteed.

The Deadline That Actually Matters Right Now

None of these increases help you if you haven't filed for the exemption in the first place. The rule is straightforward: to claim the home exemption for a given tax year, you need to have owned and occupied the property as your principal home by September 30 of the preceding year, and the claim form has to be filed by that same September 30 deadline. Miss it, and you wait a full year for the exemption to start.

For anyone who closed on an Oahu home this year and plans to live in it as a primary residence, September 30, 2026 is the date to circle. File by then and you'll be positioned to receive the exemption — including the higher $140,000/$180,000 amounts — when they take effect for the 2027-2028 tax year. The form is BFS-RP-E-8-10.3, and it can be filed online, by mail, or in person at either Real Property Assessment Division office.

What This Means If You're Buying, Selling, or Investing

For buyers closing on a primary residence this year, filing for the exemption isn't optional paperwork — it's money left on the table if you skip it. For sellers, it's worth confirming with your buyer's agent that this gets flagged during escrow, since it's easy to lose track of amid closing logistics. For investors, remember the exemption only applies to owner-occupied homes; a non-owner-occupied property doesn't qualify and falls under the higher Residential A rates instead, so this doesn't change the math on rental purchases.

If you own on Maui, Kauai, or Hawaii Island, the specifics differ since each county sets its own rates and exemption rules, but the underlying lesson is the same: exemptions aren't automatic, deadlines are firm, and it's worth checking your county's real property tax office each year rather than assuming your paperwork is up to date. A few minutes filing a form is a small task with a real, recurring payoff on your tax bill.