What is a plat of survey in an Illinois home purchase?
A plat of survey is a drawing prepared by an Illinois-licensed professional land surveyor that shows the lot lines, corner monuments, and visible improvements on the property you are buying. Under the Multi-Board Residential Real Estate Contract 8.0, the seller must deliver a boundary plat of survey dated within six months of closing, at least one business day before closing, unless the home is a condominium. A mortgage inspection is not a plat of survey and does not meet the contract.
By Kealan O’Neil | Published October 12, 2026 | Updated October 28, 2026
Most buyers in Yorkville, Oswego, and Montgomery spend weeks on inspections, appraisals, and loan paperwork, then see the plat of survey for the first time at the closing table. By then, a fence that sits over the line, a shed that sits in an easement, or a driveway that straddles a neighbor’s lot is expensive to fix and hard to renegotiate.
The question I hear most is how long it takes to get one, and the honest answer is that it depends on the surveyor’s schedule and the weather. That is exactly why the fix starts early: know what the contract requires, get the right document, and read it before you wire the rest of your money.
What the Multi-Board contract requires before closing
Paragraph 21 of the Multi-Board Residential Real Estate Contract 8.0, the form used across Chicago’s Western Suburbs, puts the duty and the cost on the seller. Not less than one business day before closing, except where the real estate is a condominium, the seller must furnish to you or your attorney a plat of survey that:
- Conforms to the current Minimum Standard of Practice for boundary surveys
- Is dated not more than six months before the closing date
- Is prepared by a professional land surveyor licensed in Illinois
- Shows visible evidence of improvements, rights of way, easements, use, and measurements of all parcel lines
- Has monuments or witness corners set at all accessible corners, with those corners visibly staked or flagged
- Includes this statement near the surveyor’s seal and signature: “This professional service conforms to the current Illinois Minimum Standards for a boundary survey.”
The same paragraph says a mortgage inspection, as defined, is not a boundary survey and is not acceptable. That one sentence is where a lot of Fox Valley closings go sideways.
Paragraph 20 ties the survey to title. If the title commitment discloses unpermitted exceptions, or if the plat of survey shows encroachments or other survey matters that are not acceptable to you, the seller must have those items removed or have the title insurer commit to insure against loss from them, including court-ordered removal of encroachments, before closing. If the seller cannot, you may take title as it then is and deduct prior encumbrances of a definite or ascertainable amount from the purchase price. Your attorney runs that call, not the listing sheet.
5 mistakes buyers make with a plat of survey
1. Accepting a mortgage inspection instead of a boundary survey
Lenders and title companies sometimes rely on a mortgage inspection to see how the house sits relative to the deed lines. Illinois administrative rules are blunt about what that product is. Under 68 Ill. Adm. Code 1270.56, a mortgage inspection is not a boundary survey, no monuments are set, and it is not to be used for boundary disputes, legal actions between landowners, or construction.
The same rule requires the drawing to carry the title “MORTGAGE INSPECTION THIS DOES NOT CONSTITUTE A BOUNDARY SURVEY” in letters twice the size of the rest of the lettering. If you see those words, you are not holding the document Paragraph 21 calls for.
If someone hands you a mortgage inspection the morning of closing, that is not compliance. Ask your attorney to reject it and require a true boundary survey under Paragraph 21.
2. Waiting until the day before closing to look at it
The contract only requires delivery one business day before closing. That is a floor, not a plan. A fence that crosses the line, a retaining wall in an easement, or a missing corner monument can take days to straighten out with the surveyor, the title company, and both attorneys.
In practice, I ask the seller’s side to order the plat of survey as soon as the inspection contingency is underway, and I ask for a PDF as soon as the fieldwork is done. Your attorney can compare it to the title commitment while there is still time to use Paragraph 20. Waiting until the final walkthrough week is how buyers end up choosing between delaying closing and living with a problem.
One cost note: because the contract puts the survey on the seller, it usually should not show up on your side of the settlement statement. If it does, ask why. Here is what normally belongs in your column in our guide to buyer closing costs in Yorkville.
3. Assuming an old survey or a subdivision plat is good enough
A recorded subdivision plat shows how the lots were created. It is not a current field survey of your specific house, fence, deck, or shed. The Multi-Board rule is a plat of survey dated within six months of closing. An older survey from a prior sale, even if it looks neat, does not meet that requirement unless the parties agree otherwise in writing.
New construction has its own wrinkle. The Illinois minimum standards let a surveyor delay setting corner monuments when construction or grading would disturb them, but they must be in place within 12 months of the last fieldwork. If you are closing on a new build in a Yorkville or Oswego subdivision, ask whether the corners are actually set or still pending, and get that answer in writing before closing. If grading or landscaping is also unfinished, an escrow holdback may be part of the same conversation.
4. Skipping the license and the seal check
Illinois requires a licensed professional land surveyor for this work under the Illinois Professional Land Surveyor Act of 1989 (225 ILCS 330). The state’s minimum standards require the plat to show the surveying firm’s name, address, and registration number, along with the surveyor’s seal, signature, date of signing, and license expiration date. You can verify the license on the IDFPR Check License site before you rely on it.
Also look for the exact minimum-standards statement near the seal. If that sentence is missing, or the drawing is labeled as something other than a boundary survey, send it back. A neat PDF from an unlicensed preparer is not a valid boundary survey under Illinois rules.
5. Ignoring fences, sheds, and easements on the drawing
The whole point of the survey is what it shows on the ground: the house, garage, driveway, fences, decks, sheds, and visible utilities, plus easements and rights of way. Compare those marks to what you walked at the inspection.
A fence a foot onto the neighbor’s lot may be something you can live with, or it may be something title will not insure without an endorsement or an agreement. A shed sitting in a drainage easement can become a removal order later. Those are Paragraph 20 problems, and they are also why title insurance and the survey have to be read together. Do not treat the survey as a formality while you focus only on the appraisal and the loan.
Why your plat of survey matters after closing in Yorkville and Montgomery
The survey you get at closing is not a one-time document. It is usually the first thing your village or city asks for when you want to add a fence, a shed, a deck, or a pool, so read it now with your future projects in mind.
Yorkville permits
The United City of Yorkville’s building permit information page says that in most cases a copy of a recent plat of survey will be required, showing existing buildings and the proposed improvement with dimensions and distances to all lot lines. Yorkville’s fence permit application goes further: a plat of survey showing the fence location must accompany every fence permit application or alteration to an existing fence. If you plan to build within a utility easement, the city also asks for a notarized Release and Hold Harmless Agreement.
Montgomery permits
The Village of Montgomery’s fence permit requirements ask for a plat of survey or as-built drawing with the fence location marked, and the village describes it as the property map you received at closing. The same page says fences, including posts, must sit completely within the lot, and the owner is responsible for removal and replacement if a fence in an easement has to come out. Montgomery’s building permit application also says exterior construction and additions require a current plat of survey.
Oswego and the rest of the Fox Valley
Oswego and most neighboring towns also require permits for fences and accessory structures, and their checklists change, so confirm the current submittal list with the village building department before you hire a contractor. If the survey shows a shed, deck, or patio the seller added without a permit, that is worth raising now, and our post on unpermitted work in Oswego walks through how to handle it under contract.
Why the right agent matters for the plat of survey
A good agent does not replace your attorney or the surveyor. The agent’s job is to keep the timing honest and make sure the right document shows up early enough to matter. Here is the order I use with buyers in Kendall and Kane County:
- Confirm the property type. Condos are exempt from Paragraph 21. Most single-family homes and many townhomes are not. Ask which box your attorney expects.
- Put the survey on the calendar early. Ask the listing side who is ordering it, which surveyor, and when fieldwork is scheduled.
- Get the PDF to your attorney as soon as it exists. Do not wait for the original paper at closing.
- Walk the corners if they are flagged. Match the stakes to the fence, driveway, and shed before you sign anything else.
- Escalate problems in writing. Encroachments and missing monuments go to your attorney under Paragraph 20, with a clear ask: remove, insure over, credit, or delay.
- Keep the survey with your closing file. You will need it again for a fence, a pool, a shed, or a future sale.
That process is the same kind of mid-deal discipline I recommend for the inspection contingency and the attorney review period. The numbers on the loan matter. So do the lines on the ground.
Questions Yorkville buyers ask about surveys at closing
These come up on almost every resale closing I handle in Kendall County.
Who pays for the plat of survey in Illinois?
Is a mortgage inspection the same as a plat of survey?
How recent does the plat of survey need to be, and how long does it take to get?
What if the plat of survey shows an encroachment?
Do I need a plat of survey for a fence permit in Yorkville or Montgomery?
Read the lines before you take the keys
A plat of survey will not make a bad house good. It will tell you whether the house, fence, and driveway sit where you think they do, and it is the document you will hand the city the first time you want to build something. In Yorkville, Oswego, Montgomery, and the rest of Chicago’s Western Suburbs, that check belongs in the same week as your inspection, not the morning you are supposed to close.
If you are under contract and the survey has not been ordered yet, or you have a PDF and are not sure what you are looking at, send it over. I will help you coordinate with your attorney, compare it to the title commitment, and decide what needs to be fixed before the final walkthrough. Call or text Kealan at 630-425-8815.
This post is part of our Illinois purchase contract guide.
About Kealan O’Neil
Kealan O’Neil is the Designated Managing Broker and founder of O’Neil Property Group, an independent real estate brokerage based in Yorkville, Illinois. He and his team help buyers and sellers in Yorkville, Oswego, Montgomery, and the surrounding Kendall and Kane County communities, and he owns and manages a local rental portfolio, so he approaches every decision as both a broker and an investor. Call or text Kealan at 630-425-8815.
This post is general information about real estate in the Fox Valley, not legal, tax, or financial advice. Real estate laws, tax rules, and municipal ordinances change, and how they apply depends on your specific situation. Talk with a licensed attorney, CPA, or lender before making decisions about a purchase, sale, or tax matter. O’Neil Property Group is a licensed Illinois real estate brokerage.