Indiana homeowners opened their new 2026 property tax bills this month and a lot of them are staring at a 12% bump over last year, on average. The first installment is due May 10, 2026. The deadline to appeal that assessment is June 15, 2026. If you only noticed the discrepancy after filing season, you're now in a squeeze the state actually anticipates — and there's a statutory payment shield that almost nobody talks about.
It's buried in Indiana Code § 6-1.1-15-10, and it only works if you file your appeal before you send the May check.
The calendar trap
Indiana's 2025 gross assessed values rose 12% statewide, per DLGF's comparison chart for taxes payable in 2026. That increase flows directly into the bills arriving in April mailboxes.
- First installment due: May 10, 2026
- Appeal deadline (Form 130): June 15, 2026
- Late payment penalty: 5% if paid within 30 days, 10% thereafter
- Second installment due: November 10, 2026
If you just pay the full higher bill and file the appeal after, you've handed the county money you may never see again on any portion that gets reduced. If you skip the payment and appeal, you get hit with 5–10% penalties on an unreduced balance. That's the trap.
What Indiana Code § 6-1.1-15-10 actually says
Under IC 6-1.1-15-10, when a property tax appeal is timely filed and pending, the taxpayer is required to pay only the amount calculated using the immediately preceding year's assessed value, not the new disputed value. The county treats that reduced payment as timely for both May and November installments.
Two non-negotiable conditions:
- Your Form 130 must be on file before the installment date. For the May 10 window, that means filed in late April or the first week of May — not mid-June.
- If you lose the appeal, you owe the difference plus interest. Depending on your county, the treasurer may require a bond or escrow if the appeal is unresolved by November 10.
Worked example
Say your 2025 assessed value was $378,000 and your new 2026 assessment is $425,000. Your tax district's rate is, for round numbers, 2.00% of assessed value.
| Scenario | May 10 payment |
|---|---|
| Pay the new AV (no appeal) | $425,000 × 1.00% = $4,250 |
| Pay the prior AV (appeal on file) | $378,000 × 1.00% = $3,780 |
| Difference deferred until appeal decision | $470 |
Across both installments you hold back $940 on a 12% over-assessment — and if the appeal succeeds, you never write that check.
How to trigger the protection (four steps)
- Open your Form 11 assessment notice — it came in March/early April. The "Notice of Assessment" amount is your new gross AV. If it's materially higher than your home's fair market value, you likely have a case. See our Form 11 walkthrough for red flags to look for.
- File Form 130 immediately. You don't need final evidence packaged to file — you need the petition on record. Supplementary evidence can follow. The filing itself triggers the § 6-1.1-15-10 protection.
- Compute your protected interim payment. Multiply your 2025 assessed value by the 2026 tax rate for your district. That's what you send on May 10 — not the billed amount.
- Write a cover memo. With your check or ACH, include a short note to the county treasurer: "Form 130 appeal filed [date]; payment calculated per IC 6-1.1-15-10 on 2025 assessed value pending appeal resolution." This prevents the treasurer from flagging your account delinquent.
What to expect after May 10
The county processes the payment as timely. Your appeal enters the PTABOA queue. Best-case, you get a decision before November — we've seen average timelines of 90–150 days in heavier counties like Marion and Lake. If the 180-day inaction rule triggers, you can escalate to the Indiana Board of Tax Review and the interim-payment protection carries over.
Common mistakes
- Filing on June 15 instead of April/May. Legal, but too late for May installment protection. The late-May and June 10+ filers still get appeal rights, just not the payment shield for the first installment.
- Paying the full new bill, then filing. Getting money back from the county after a successful appeal is a refund process that can take 6–12 months. Keeping the money in your pocket via § 6-1.1-15-10 is cleaner.
- Forgetting the bond trigger. If your appeal drags past November and the dispute is material, ask your treasurer whether a bond or escrow is required. Most counties won't demand one on a residential case under $10K in dispute, but commercial taxpayers should budget for it.
What makes an appeal worth filing
Our property tax appeal guide covers the evidentiary bar in detail, but the short version: you need comparable sales that put your property's market value in use below the county's assessed value. Indiana is a "market value in use" state — not replacement cost, not insurance value. If three to five recent sales of similar homes in your neighborhood closed below your assessment, you have a case.
Running AribaTax's free county analysis is the fastest way to see whether your assessment is an outlier before you commit to an appeal.
Bottom line
The May 10 installment is an asymmetric deadline. Filing your appeal in the week before it arrives earns you a statutory payment cap that costs nothing if you win and defers nothing if you lose. Filing after it costs you the shield for both installments of 2026.
If your 2026 Form 11 felt off, get the petition on file now — not in June.