McHenry County is rare in Illinois: it explicitly tells homeowners they can draw their own site plans and construction documents without hiring a design professional.
But "you can draw it yourself" doesn't mean you can draw it on a napkin. Since January 2025, all permit applications are fully digital, which means your site plan must be a clean, properly labeled PDF that a reviewer can clearly evaluate in 10 business days.
Do You Need a Site Plan for a Small Permit in McHenry County?
Yes. If your project in unincorporated McHenry County requires a building permit, you must submit a site plan.
According to the county's official Site Plan Applicant Checklist, your plan must include:
- Lot lines and dimensions with the total parcel size (in acres or square feet).
- A graphic scale bar (e.g., 1 inch = 50 feet).
- A North arrow.
- All existing structures on the parcel, including the house, outbuildings, well, and septic.
- The proposed construction, clearly dimensioned.
- Setbacks (the distance from the proposed structure to all property lines).
- Adjacent roads and streets (both improved and unimproved).
Who Runs Into This in McHenry County
- Crystal Lake residents who apply for a permit through the McHenry County Planning and Development Department, only to be redirected to the City of Crystal Lake building department.
- Rural homeowners who build a 160-square-foot storage shed believing it is exempt, not realizing McHenry County's exemption limit is 150 square feet—10 feet smaller than many assume.
- DIYers who submit a blurry cell phone photo of their hand-drawn sketch through the digital portal, resulting in an immediate rejection because it is illegible.
- Contractors who forget to include a culvert certificate for a new driveway, triggering an otherwise-avoidable delay in plan review.
What Needs a Site Plan in McHenry County
- Fence permit site plan — Privacy fences (less than 50% see-through) require a permit and a site plan. Non-privacy fences (50% or more see-through) are exempt from permits.
- Shed permit site plan — Required for sheds 150 sq ft or larger. (Sheds under 150 sq ft are exempt from building permits if properly anchored, but zoning setbacks still apply).
- Deck permit site plan — Required for any deck attached to a house. The county requires a minimum frost depth of 42 inches.
- Pool permit site plan — Required. Health Department review may also be required for certain pool types.
- Garage permit site plan — Required for detached garages over 150 sq ft.
- Addition permit site plan — Required. Must show the expanded footprint and all setbacks.
Why This Trips People Up in McHenry County
The Jurisdiction Split. McHenry County covers both unincorporated areas and numerous incorporated municipalities. Your permit jurisdiction is determined by where your property line sits on a map, not your mailing address. Use the McHenry County GIS to confirm you are in unincorporated territory before applying to the county.
The 150 Sq Ft Exemption. McHenry County's threshold is 150 square feet, not the 120 or 200 square feet common in other states. A 10x15 shed (150 sq ft exactly) sits right on the line. A 10x16 shed (160 sq ft) requires a full permit. Additionally, the shed must be "properly anchored" to qualify for the exemption—a shed placed on patio blocks without anchoring does not qualify.
Fully Digital Applications. Since January 2025, the county no longer accepts paper applications. Everything must be submitted through the online portal in PDF format. A hand-drawn sketch photographed with a phone cannot be uploaded successfully as a legible, scalable document.
Construction Scale Requirements. For buildings that do require construction plans (garages, additions, decks), the county requires two sets at a 1/4" = 1'-0" scale. Truss certificates must be signed and sealed by an Illinois Structural Engineer or Architect—this is one area where a professional is required.
Zoning and Setbacks in McHenry County
Setbacks are governed by the McHenry County Unified Development Ordinance (UDO).
R-2 Residential Zone Example:
- Front: 30 feet minimum
- Interior Side: 7 feet minimum (18 feet combined)
- Rear: 20 feet minimum
Accessory Structure Setbacks:
- Sheds and detached garages typically require a minimum of 3 to 5 feet from side and rear property lines.
- Height is measured to the highest point of the structure.
How the Tool Handles This — 5 Steps
Our Site Plan Maker Online webtool loads McHenry County parcel data so you can generate the clean PDF site plan the county's digital portal requires:
- Enter your address — Lot lines load from [county GIS records](www.mchenrycountygis.org).
- Place your project — Add your shed, deck, or garage to the lot.
- Set the graphic scale — Generate the plan with a clear scale bar (e.g., 1" = 50'), as required by the county checklist.
- Label the setbacks — Drop dimension lines from your proposed structure to all property lines.
- Export a clean PDF — Download a professional, legible plan ready for upload through the county's online permit portal.
Where This Tool Fits — and Where It Doesn't
| Situation | Best path |
|---|---|
| Shed, deck, or addition in unincorporated McHenry County | SitePlans.ai for the required homeowner-drawn site plan |
| Verifying setbacks for an exempt shed under 150 sq ft | SitePlans.ai to visualize layout and avoid zoning violations |
| Structures with trusses | Licensed IL Structural Engineer/Architect required for truss certificates |
| New home construction | Licensed professional seal required |
| Disputed property lines | Licensed Land Surveyor required |
What This Doesn't Replace
SitePlans.ai helps create preliminary, conceptual site plans for residential projects where McHenry County allows homeowner-prepared drawings. It is not a licensed land survey or sealed engineering drawing. Truss certificates for garages, additions, and other structures with trusses must be signed and sealed by a State of Illinois Structural Engineer or Architect.
Comparison: Your Options for a McHenry County Site Plan
| Method | Cost | Time | Stamp | Notes |
|---|---|---|---|---|
| Hand sketch / aerial print | Free | 30–60 min | ✗ | County-approved method; must be converted to clean PDF for digital portal |
| SitePlans.ai | Free first plan | Minutes | ✗ | Generates a professional, scalable PDF directly ready for portal upload |
| CAD drafter | $300–$800+ | 1–2 weeks | Sometimes | Overkill for most decks and sheds |
| Licensed surveyor | $600–$1,500+ | 2–4 weeks | ✅ | Required if property lines are disputed |
| SitePlans.us (done-for-you) | Custom | 1–3 days | ✗ | Best if your first attempt was rejected by the digital portal review |
Common Mistakes That Delay McHenry County Permits
- Wrong jurisdiction — Applying to the county when you are inside Crystal Lake, McHenry, or another incorporated city.
- Over the 150 sq ft line — Building a 10x16 shed (160 sq ft) and assuming the "under 150 sq ft" exemption still applies.
- Illegible PDF submission — Submitting a photographed hand sketch that cannot be clearly read by the digital review system.
- Missing the graphic scale bar — Forgetting to include a scale bar on the site plan (a specific checklist requirement that will halt review).
- No culvert certificate for driveway — Adding a new driveway without the required culvert certificate, causing a plan review delay.
- Un-anchored exempt shed — Building a small shed on patio blocks and assuming it is exempt, when the county requires it to be "properly anchored."
Support and Local Resources
- McHenry County Planning and Development — mchenrycountyil.gov — Call (815) 334-4560.
- McHenry County GIS — mchenrycountygis.org/planning — Print your aerial photo here.
- Online Permit Portal — Accessible via the county's Planning and Development website.
- FEMA Flood Maps — msc.fema.gov
Nearby Counties in Illinois Requirments
Frequently Asked Questions
1. Does McHenry County allow homeowners to draw their own site plans?
Yes. For unincorporated McHenry County, construction documents for residential permits do not need to be prepared by an architect or design professional. You can draw your site plan on an aerial photograph, a plat of survey, or the county's provided form.
2. Do I need a permit for a shed in McHenry County?
Accessory structures under 150 square feet that are properly anchored are exempt from building permits. If your shed is 150 square feet or larger, a building permit and site plan are required.
3. Do I need a permit for a fence?
Non-privacy fences (those that are 50% or more see-through, like chain-link or split-rail) do not require a permit. Privacy fences do require a permit and a site plan.
4. How do I submit my site plan in McHenry County?
Since January 2025, all applications are submitted digitally through the county's online permit portal. Paper applications are no longer accepted. Your site plan must be in PDF format and legible at a clear scale.
5. How long does permit review take?
Plan review typically takes 10 business days. A non-refundable review fee of $75 or 25% of the permit fee (whichever is greater) is required at the time of application.
6. Can I use SitePlans.ai for a McHenry County permit?
Yes. SitePlans.ai generates a clean, properly scaled PDF with all the required site plan elements—lot lines, North arrow, scale bar, setback dimensions, and existing/proposed structures—ready for upload to the county's digital portal.
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Start Your McHenry County Site Plan
Check your jurisdiction on the McHenry County GIS first. Then, enter your address below to pull your property lines, place your project, label your setbacks, and download the clean, scalable PDF you need for the county's digital permit portal.
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