Building Permit Cost in Decatur, IL (2026)
Typical residential building permits in Decatur run $25–$5,000, 486% above the Illinois state average. Fees vary by project type, scope, and declared valuation.
By Joey, Founder · Last verified March 28, 2026 · How we research →
The short answer
Expect $25–$5,000 for most residential permits in Decatur. That's 486% above the Illinois state average of $167–$691.
Simple swaps (water heaters, EV chargers, like-for-like HVAC) usually run under $200. Additions, pools, and kitchen remodels are the expensive end. Confirm current rates with Building Inspections Division at (217) 424-2787.
Permit fees by project type in Decatur
Each row shows the estimated fee range for that project type in Decatur, the typical approval timeline, and how it compares to the Illinois state average.
| Project | Est. fee in Decatur | vs state avg | Typical timeline |
|---|---|---|---|
| Deck | $85 – $510 | in line | about 3 weeks |
| Fence | $42 – $170 | −25% | about 2 weeks |
| Shed | $42 – $212 | −37% | about 2 weeks |
| Roof Replacement | $85 – $680 | in line | about 3 weeks |
| Windows and Doors | $63 – $255 | −22% | about 2 weeks |
| Bathroom Remodel | $42 – $510 | −19% | about 3 weeks |
| Kitchen Remodel | $63 – $425 | −22% | about 2 weeks |
| Swimming Pool, Hot Tub, or Spa | $42 – $680 | −19% | about 3 weeks |
| Electrical Work | $42 – $510 | in line | about 2 weeks |
| Plumbing Work | $42 – $340 | +17% | about 2 weeks |
| HVAC | $63 – $425 | in line | about 2 weeks |
| Garage | $85 – $680 | −36% | about 3 weeks |
| Room Addition | $170 – $1,700 | −39% | about 4 weeks |
| Basement Finishing | $85 – $510 | −38% | about 2 weeks |
| Retaining Wall | $85 – $425 | −19% | about 2 weeks |
| Solar Panels | $150 – $500 | in line | about 4 weeks |
| Patio | $100 – $500 | in line | about 2 weeks |
| ADU | $500 – $5,000 | +15% | about 6 weeks |
| Driveway | $75 – $500 | +13% | about 3 weeks |
| Demolition | $100 – $1,000 | +18% | about 3 weeks |
| EV Charger | $75 – $500 | +29% | about 3 weeks |
| Generator | $75 – $1,500 | +58% | about 4 weeks |
| Gas Line | $50 – $400 | +13% | about 2 weeks |
| Water Heater | $25 – $500 | +10% | about 2 weeks |
| Tree Removal | $25 – $500 | +36% | about 3 weeks |
| Siding | $100 – $800 | +12% | about 2 weeks |
| Fireplace | $75 – $800 | +46% | about 2 weeks |
| Concrete Slab | $75 – $600 | +19% | about 2 weeks |
Fees are estimates based on Decatur's rule data and may not include sub-permits (electrical, plumbing, mechanical) required for larger projects. The "vs state avg" column compares the midpoint of each range to the Illinois statewide average for the same project type.
How Decatur's permit fees are structured
Most city permit fees break down into four buckets. The exact split varies, but these proportions hold across most US jurisdictions we track.
Decatur vs state vs national averages
Midpoint of the estimated range for a typical residential permit.
How to reduce your permit cost in Decatur
- Ask about over-the-counter permits. Many jurisdictions issue same-day permits for simple projects (water heater swap, like-for-like windows, small sheds). Saves a full plan-review cycle.
- Pull the permit yourself. Owner-builder permits are usually the same fee as contractor permits, minus the contractor markup. Most cities (including Decatur where owner-builder is allowed) let homeowners file directly.
- Submit complete plans the first time. Resubmittals often trigger a re-review fee. A clean first submittal is typically the single biggest driver of cost and timeline.
- Check if your project is exempt. Small fences, low decks, minor electrical, and like-for-like appliance swaps are often permit-exempt. Use our free lookup tool to check your specific project before assuming you need one.
- Bundle related work. If you're doing multiple upgrades, applying for them together is usually cheaper than separate permits, because plan review and inspection fees are often priced per-visit.
Who to call in Decatur
Check if your project needs a permit in Decatur
Free instant answer with the municipal code section cited.
Frequently asked questions
How much does a building permit cost in Decatur, IL?
Most residential building permits in Decatur run $25–$5,000, depending on the project type and valuation. Simple permits like water heater replacements can be under $100, while additions and pool permits run into the low thousands.
Why are permit fees different in Decatur than other cities?
Every city sets its own fee schedule. Fees typically scale with project valuation and cover building-permit review, plan review, inspections, and a small technology or records fee. Decatur publishes its fees separately from surrounding jurisdictions, so the same project can cost materially more or less one town over.
Do I have to pay the permit fee even if the city denies the permit?
Most jurisdictions charge a non-refundable plan-review fee at submission, which stays with the city even if the permit is ultimately denied. The balance (permit issuance and inspection fees) is typically refunded or never collected. Confirm with Building Inspections Division before you file.
Can the permit fee go up after I apply?
Yes. Most cities recalculate fees once plan review is complete if the declared project valuation changes, or if additional sub-permits (electrical, plumbing, mechanical) are required. Budget for a 10–15% buffer over the estimate.
Is there a way to lower my Decatur permit cost?
A few practical options: file for an over-the-counter permit if your project qualifies, submit complete plans the first time to avoid resubmittal fees, pull the permit yourself instead of paying a contractor's markup, and check whether your project is exempt (small sheds, low fences, like-for-like water heater swaps often are).