In most Chicago suburbs, an inspection contingency does one job: it tells you whether the systems in the house work. In Long Grove, where the majority of homes sit on private well and septic rather than municipal water and sewer, that same word, "passed," can mean something much narrower than buyers assume. Understanding exactly how narrow is the difference between negotiating from real information and negotiating from a false sense of security.

What the county actually checks

When a Long Grove sale involves a private well and septic system, it's common for a lender or buyer to request an evaluation from the Lake County Health Department. That evaluation is genuinely useful. Staff pull records to see if a system plan exists, review any past complaints or service requests on file, walk the property to look for visible signs of failure, and, if requested, collect a water sample tested for coliform bacteria and nitrates.

What it does not do is where most buyers get surprised. The department's own description of the service is direct about the limits: the septic inspection does not include opening the tank, checking its interior condition, or pumping it. The well inspection does not measure how many gallons per minute the well can actually deliver, which matters a great deal on a property with irrigation, a pool, or multiple bathrooms running at once. If you want either of those things checked, you need to hire a private contractor separately.

Here's the split in plain terms:

The county is also candid that the evaluation itself is not a guarantee of future performance, and that there's no state or county statute requiring it in the first place. Lenders ask for it. Buyers ask for it. It's a real estate custom, not a legal mandate, and there's no standardized inspection protocol behind it. Two evaluators could reasonably look at the same system and describe it differently.

The disclosure form has the same gap

Illinois sellers complete a Residential Real Property Disclosure Report before a buyer signs a contract, and two of its standard questions ask directly about known defects in the well or well equipment and in the septic or sanitary sewer system. That sounds like solid protection until you read the form's own definition of "aware." Under the statute, a seller only has to disclose what they have actual knowledge of, with no obligation to investigate or test anything first.

That single clause explains a lot. A seller who has lived in a Long Grove home for fifteen years without ever having the septic tank pumped or the well flow-tested can honestly check "no known defects" on the disclosure form, not because the system is sound, but because nobody has looked closely enough to find a problem. The form protects buyers from concealment. It does nothing to protect them from a seller's own lack of information.

Layer that on top of the county evaluation's scope limits and the picture gets clearer: a clean disclosure form plus a passed county evaluation tells you the system probably isn't failing visibly right now. It tells you almost nothing about tank condition, well capacity, or how many years of service are actually left. The University of Illinois Extension has flagged the financial stakes here directly, noting that replacing a private onsite system can approach $10,000, which is exactly why more buyers and lenders now push for a professional inspection report before closing rather than relying on the disclosure form alone.

The permit you didn't know you'd need

Say you close on a Long Grove home and the septic system needs replacing within the first year or two. Most buyers assume that's a single call to a contractor and a single permit. It isn't. The Village of Long Grove's building department states plainly that replacing a septic system requires an electrical permit issued by the Village, while the septic permit itself has to be obtained separately from the Lake County Health Department. Two different agencies, two different applications, two different timelines to coordinate around a single project.

It gets one layer more complicated depending on where in Long Grove the property sits. The Village notes that most residents are incorporated and follow Village ordinances, but some parcels are unincorporated, and owners are told to check their property tax bill to determine which applies. Unincorporated owners handle building and zoning matters directly with Lake County instead of the Village. If you're comparing two Long Grove listings that look identical on paper, this is worth confirming before you assume the post-closing process will look the same for both.

None of this should scare a buyer away from a well-and-septic property. It should change what you ask for before you remove contingencies.

Why this matters more in today's market than it did a year ago

Long Grove's market has slowed in a way that actually works in a careful buyer's favor. Over the three months ending in May 2026, the median sale price came in around $960,000, down roughly 8.6 percent from the same period a year earlier. Read alone, that number suggests a market losing value. It doesn't hold up under a second look. Over that same stretch, the median price per square foot rose about 10 percent year over year, and homes took a median of 65 days to sell compared with 38 days the year before.

Put those together and a different story emerges. Per-square-foot value is climbing, not falling. What moved the median down was almost certainly a shift in which homes sold during that window, not a broad decline in what Long Grove properties are worth. Combine that with buyers taking nearly twice as long to close as they did a year ago, and you have a market where sellers are less able to demand waived contingencies and more likely to accept a request for an independent septic and well inspection as a normal part of the process.

That's the leverage point. In a market where homes sold in 38 days, asking a seller to fund a pump-out and tank inspection, or a private flow-rate test on the well, might have felt like a deal-breaker. At 65 days, it's a reasonable ask that a motivated seller is more likely to accommodate, whether through a credit, a pre-closing repair, or simply agreeing to the extra time it takes to schedule.

What to actually ask for

Before you remove an inspection contingency on a Long Grove property, get three things beyond the standard county evaluation: a private contractor's assessment of the septic tank's interior condition, including when it was last pumped, a flow-rate test on the well if the county's visit didn't include one, and a straight answer from the seller's agent about whether the property is incorporated or unincorporated, since that determines who you'll be calling if the system needs work later. None of these cost much relative to what a system replacement runs, and all three give you something the disclosure form and the county evaluation, on their own, cannot.

Does every home in Long Grove rely on well and septic? Not every property, but private systems are common enough throughout the village that it's worth confirming for any specific listing rather than assuming either way.

Is a septic evaluation legally required before closing in Illinois? No. The Lake County Health Department is explicit that there's no statutory requirement for a routine evaluation. Lenders and buyers request it as standard practice, not because the law demands it.

If I buy a home with an aging system, do I have to work with both the Village and the County? If the property is incorporated and the system needs replacement, yes. You'll need an electrical permit from the Village of Long Grove and a separate septic permit from the Lake County Health Department. Unincorporated properties route through the County directly.

A well and septic system shouldn't be the thing that catches you off guard after you've already fallen for the house. If you're weighing a Long Grove property and want a second set of eyes on what a disclosure form and a county evaluation actually cover before you write an offer, Maria Devins has spent years negotiating exactly these details for buyers in Long Grove's estate market. Reach out for a conversation, or get your instant home valuation if you're on the selling side of this same equation.