A house does not change size between the listing and the closing. The number attached to it can, though, depending on who measured it, what they counted, and whether anyone checked before it went live. That gap is where a lot of quiet professional risk lives, and most agents never think about it until a buyer stands in a newly purchased home with a tape measure and a bad feeling.
Square footage is one of the few numbers in a listing that a buyer can independently verify after the fact. Price is negotiated. Condition is disclosed and inspected. But square footage is a claim, and when the claim turns out to be materially off, people look for someone to hold responsible. Often the first name in that conversation is the listing agent’s.
This is not a reason to panic. It is a reason to understand where the number comes from and where the responsibility actually sits, because the answer is less comfortable than “the county said so.”
Where the number actually comes from
Most agents pull square footage from one of three places: the county or municipal assessor’s record, a prior MLS listing, or a measurement someone took (an appraiser, a builder’s plan, or the agent’s own walk-through). Each of those sources has a different reliability problem.
Assessor records are built for taxation, not for marketing accuracy. Assessors measure from the exterior, estimate in some cases, and do not always update after additions, finished basements, or conversions. A finished lower level that adds real usable space may not show in the above-grade figure at all, or a three-season room may be counted when it should not be. The number is not fabricated, but it was never designed to be the marketing spec a buyer relies on.
A prior MLS listing is often just a copy of a copy. If the number was wrong the first time it was entered, every listing after that inherits the error, and each agent who repeats it is quietly vouching for a figure they never checked.
An actual measurement, done to a recognized standard, is the most defensible source. In Michigan, MichRIC and most local boards point agents toward measuring consistently, disclosing the source of the figure, and distinguishing above-grade from below-grade space. The ANSI measurement standard is the common reference point for how finished area should be calculated. The important part is not memorizing the standard. It is understanding that “square footage” is not one universal number, and that below-grade finished space is generally not counted the same as above-grade living area.
Where the liability sits
Here is the part agents tend to get wrong. The instinct is to assume that if the seller gave you the number, or the county published it, you are covered. In practice, a licensed agent is held to a professional standard of care. You are not just a messenger passing along whatever you were handed. You are expected to have a reasonable basis for the material facts you publish, and to not misrepresent them, whether the misrepresentation is intentional or the result of not checking.
The NAR Code of Ethics, in Article 2, is direct about this: agents are to avoid exaggeration, misrepresentation, or concealment of pertinent facts. It does not carve out an exception for facts you copied from somewhere else in good faith. Michigan license law similarly expects honest dealing and reasonable care. A number you published becomes, to some degree, a number you stood behind.
That does not mean an agent is automatically on the hook for every discrepancy. Reasonableness matters, disclosure of the source matters, and the size of the error matters. A 40 square foot difference on a 2,400 square foot home is unlikely to move anyone. A 400 square foot difference that changed how a buyer valued the home is a different conversation, and the buyer’s first question will be where the number came from and whether anyone verified it.
The uncomfortable truth is that “the seller told me” and “the county said so” are explanations, not shields. They may reduce your exposure. They do not erase your responsibility to have exercised reasonable care.
What actually protects you
The good news is that protecting yourself here is mostly a matter of habit, not heroics.
Disclose the source of the square footage every time. If the figure came from the assessor, say so. If it came from a prior listing, treat that as a yellow flag and verify before repeating it. Naming the source does two things: it tells the buyer where to direct their own verification, and it documents that you did not present an estimate as a precise measurement.
Tell buyers to verify what matters to them. A short, standard line encouraging buyers and their agents to measure independently if square footage is important to their decision is not a cop-out. It is honest, and it moves the responsibility for relying on the number to the party who is relying on it. Many boards and forms already include measurement-disclaimer language for exactly this reason. Use it, and do not treat it as boilerplate you can ignore.
Separate above-grade from below-grade space. If a home has a beautifully finished basement, market the finished basement as what it is rather than folding it into the main square footage figure. Buyers still value it. You just avoid overstating the number that appraisers and future agents will scrutinize.
When the number matters and the sources disagree, get a measurement. On higher-value homes, on homes with additions or conversions, or any time the assessor record and the prior listing do not match, the cost of a professional measurement is small next to the cost of a discrepancy claim. This is one of those places where spending a little protects a lot.
The part that is genuinely yours
It would be easy to read all of this as a story about how the county, the seller, and the last agent set you up. Some of that is real. Records are imperfect and inherited errors are common. But the through-line of this lane is that professional responsibility does not get to be someone else’s job. The seller owns their disclosures. The assessor owns their records. And the agent who publishes a material number to the market owns the reasonable care behind it.
That is not a burden so much as a form of control. The things that protect you here are all things you can do without anyone’s permission: name your source, verify when it counts, disclose clearly, and measure when the stakes are high enough. None of that requires a better brokerage, a new tool, or a rule change. It requires deciding that the numbers you attach your name to are numbers you are willing to stand behind.
A house does not change size. Make sure the number you publish does not either.
FAQ
Can a real estate agent be held liable for wrong square footage in Michigan? Potentially, yes. A licensed agent is held to a standard of reasonable care and honest representation. Copying a figure from the county or a prior listing is an explanation, not automatic protection, especially if the error was material and no source was disclosed. Verifying and disclosing the source of the number is what reduces exposure.
Where should agents get square footage from? The most defensible source is a measurement done to a recognized standard (such as ANSI), which distinguishes above-grade from below-grade finished space. Assessor records and prior listings can be starting points, but they were not built for marketing accuracy and should be verified when the number matters.
Does a measurement disclaimer protect the agent completely? No single line makes liability disappear, but disclosing the source of the figure and encouraging buyers to verify independently is meaningful. It documents that you did not present an estimate as a precise fact and directs the relying party to confirm what matters to them.
Should finished basement space be included in square footage? Generally, below-grade finished space is counted separately from above-grade living area under common measurement standards. Market the finished basement as the valuable space it is, but do not fold it into the main square footage figure, which can overstate the number appraisers and future agents will scrutinize.
What is a “material” square footage error? There is no fixed threshold, but the question is whether the difference would reasonably affect how a buyer valued or decided on the home. A small variance on a large home is unlikely to matter. A large discrepancy that shaped the buyer’s decision is the kind that turns into a claim.
This article is educational and not legal advice. For your specific situation, review your board’s forms and standards and consult your broker or a real estate attorney.