Adams County sits in the heart of northeast Indiana's manufacturing-and-farming economy, and its 2026 assessment cycle reflects both halves. Form 11 notices reach Decatur and the surrounding county mailboxes by mid-April, carrying AVs shaped by the DLGF cost-table reset that pushed statewide assessed values up roughly 12% in the 2025 cycle. The Adams County tax list was last updated in late March 2026, and the spring installment is due May 11, 2026. The Form 130 appeal window runs 45 days from the notice date — typically converging on mid- to late June.
This guide breaks down what's distinctive about Adams County's 2026 cycle, what the cost-table reset means for manufacturing improvements and farmland alike, and how to file an appeal that survives PTABOA review.
What's Driving Adams County AVs in 2026
1. Manufacturing Improvement Costs Hit Hard
The DLGF cost-table reset adjusts the per-square-foot replacement cost values used to value improvements. For commercial and industrial structures — particularly the manufacturing and food-processing facilities that anchor Adams County's tax base — the multipliers compound across square footage. A 100,000 sq ft manufacturing building absorbs the cost-table adjustment at scale, producing larger absolute AV gains than residential parcels even when the percentage move is similar. Owners of large industrial parcels around Decatur should expect Form 11 movement consistent with what we documented in Marion County's commercial assessment surge.
2. Farmland Productivity Recalibration
Adams County's tillable acreage runs into the hundreds of thousands. Farmland AV is set by a base rate per acre adjusted by soil productivity factors derived from USDA NRCS soil maps. Indiana's farmland values for 2026 are coming off a multi-year run of input-cost pressure and softer commodity prices, but the assessor's base rate is set by formula and lags the market. Verify that the soil productivity factor on your Form 11 matches your actual NRCS data — incorrect productivity ratings are one of the most recoverable errors in farmland assessment.
3. Decatur's Older Housing Stock
Decatur's downtown and older residential neighborhoods carry a meaningful concentration of pre-1940 housing. Functional obsolescence — small bedrooms, single bathrooms, no central air, outdated electrical, lack of insulation — is appropriate to document and submit as part of any Form 130 appeal. Condition adjustments captured here apply across the next assessment cycle.
Adams County mails Form 11 in mid-April. The 45-day appeal window runs from your specific notice date — not from a fixed statewide date. If your notice is dated April 18, your deadline is approximately June 2. Do not assume June 15 applies to your parcel; check the date printed on the Form 11.
What to Check on Your Adams County Form 11
Use the statewide Form 11 walkthrough for the general process. Three Adams-specific items deserve focused attention.
Property Class Code
Verify:
- Owner-occupied residence is coded 510, not 511 (rental)
- Manufacturing structures are coded for the actual use, not generic commercial
- Farm-with-residence parcels have separate coding for the home and the tillable acres
- Outbuildings used for non-ag commercial purposes are not still coded as ag
Farmland Soil Productivity
Pull your NRCS soil map (free at the USDA Web Soil Survey) and compare the dominant soil types against the productivity factor on your Form 11. A misapplied productivity factor of even 5–10% can compound across hundreds of acres into a substantial AV swing.
Manufacturing Improvement Detail
For industrial parcels, verify:
- Square footage matches actual measured area
- Building class (warehouse, light manufacturing, heavy manufacturing) reflects actual use
- Obsolete or out-of-service portions are noted as such
- Bolt-on additions are coded with the correct year of construction
Adams County By the Numbers
| Metric | Adams County |
|---|---|
| County seat | Decatur |
| Population (approx.) | 36,000 |
| Median tax bill | ~$1,450 |
| Constitutional caps | 1% / 2% / 3% |
| Spring tax due | May 11, 2026 |
| Fall tax due | November 10, 2026 |
| Form 11 mailing window | Mid-April 2026 |
Filing a Form 130 in Adams County
Where to File
Form 130 is filed with the Adams County Assessor's Office at the county courthouse in Decatur. Filings are time-stamped on receipt. Hand-delivery or certified mail with return receipt is the safe choice for any submission in the final week of the window.
What to Include
A complete Adams County Form 130 package should contain:
- Completed Form 130 (one per parcel)
- Stated grounds: market value challenge, condition, soil productivity, or assessment error
- Three to five comparable sales (residential) or comparable rents and cap-rate analysis (commercial)
- Photos documenting condition issues
- For farmland: NRCS soil productivity documentation
- For manufacturing: floor plan, square footage measurement, and obsolescence documentation
- Optional but persuasive: USPAP-compliant appraisal
The general Indiana property tax appeal guide walks through Form 130 evidence build in detail.
What Happens After Filing
The PTABOA acknowledges the petition and may extend a written settlement offer based on the evidence. Most Adams County appeals settle on written evidence without a formal hearing. PTABOA hearings typically schedule three to nine months after filing. PTABOA decisions can be escalated to the Indiana Board of Tax Review within 30 days of the written determination.
SB 1 and the Spring 2026 Bill
Adams County homestead owners receive the SB 1 supplemental homestead credit on the spring 2026 bill — 10% of net property tax owed, capped at $300 per homestead. The supplemental homestead deduction also steps from 35% to 40% in 2026. Decatur homestead owners should see a measurable downward shift on the spring 2026 bill that partially offsets the AV increase landing on the Form 11 notice for the following year's bill.
The SB 1 credit does not apply to manufacturing or farmland parcels — these will see the full impact of the AV increases without any offsetting credit. For Adams County's industrial taxpayers, the only mechanism to influence the 2027 bill is the Form 130 appeal on the 2026 Form 11.
Manufacturing Personal Property and SB 1's Other Lever
Beyond the homestead credit, SB 1 also raised the business personal property exemption to $1 million in 2026 and $2 million in 2027. For Adams County manufacturers and small commercial operators, this is a meaningful filing change: businesses with personal property valued under the exemption threshold do not owe personal property tax on those assets, though the filing requirement remains for documentation purposes.
This is separate from the real property AV that drives your Form 11 — but for industrial owners running both real and personal property assessments, the combined impact of the cost-table reset (which raises real property AV) and the personal property exemption increase (which lowers personal property tax exposure) needs to be modeled together.
Adams County in the Statewide Picture
Adams sits below the statewide median property tax rate and is not represented among the most over-assessed counties. It is, however, exposed to the cost-table reset on the same percentage basis as every other Indiana county — meaning the 2026 Form 11 will land with material AV increases for both residential and industrial owners. The appeal window is the only mechanism to address parcel-specific overstatements before they roll into the 2027 tax bill.
Find Your Adams County Property
- Adams County overview
- Adams residential parcel data
- Adams commercial parcel data
- Adams industrial parcel data
- Adams agricultural parcel data
For a quick read on whether your Form 11 number is defensible, Property Lookup pulls comparable sales for your neighborhood code. For a contingency-based appeal, Tax Appeal Automation builds the Form 130.