The Zestimate Gap: Pricing a Johnson County Home in a Non-Disclosure State

Almost every seller I meet already has a number in their head before I walk through the door. It usually came from a phone screen. Sometimes it came from the appraisal notice the county mailed in March. Once in a while it came from a neighbor's sale, told over a fence with the price rounded up.

None of those is the number a buyer will pay. This page is about the gap between them, why that gap is wider in Kansas than in most of the country, and how I actually arrive at a list price for a home in Johnson County. If you just want a quick starting figure, my free home valuation runs the comparable-sales math in a few minutes. If you want to understand what that figure is and isn't, read on.

Contents

• Three numbers, three different jobs
• Why online estimates miss in Kansas
• What the county appraised value measures
• How a Johnson County CMA is built
• The adjustments that move the number most here
• From a value to a list price
• Get your number

Three numbers, three different jobs

The online estimate (Zillow's Zestimate, Redfin's estimate, the one your bank app shows) is an algorithm's guess at what your home would sell for today, built from whatever data the algorithm can see. It is designed to cover every house in America, which means it is designed around the average house, not yours.

The county appraised value is what the Johnson County Appraiser's office thinks your home was worth on January 1 of this year, for one purpose: calculating property tax. It is a mass appraisal of roughly 200,000 parcels at once, and it is legally required to aim at fair market value, but nobody from the county has been inside your home.

A comparative market analysis, or CMA, is what an agent prepares before listing: a hand-built comparison of your specific home against the handful of nearby homes most like it that have actually sold, are under contract, or are sitting on the market right now. It is the only one of the three built for the question you are really asking, which is "what will a buyer pay for this house, this season?"

They can land close together. In the Johnson County price bands where I work, they often don't, and the online estimate is usually the one furthest off.

Why online estimates miss in Kansas

Kansas is a non-disclosure state. When a home sells here, the price isn't recorded as part of the public deed record the way it is in most states, and Missouri works the same way. That matters more than it sounds. The estimators are trained to lean on public sale records as their ground truth. In Kansas, they have far fewer of those records, so they fill the gap with tax-appraisal data, listing prices (not sale prices), and whatever MLS data they're licensed to see, which varies by platform and by year.

Zillow is candid about this in its own accuracy reporting. Nationally, its published median error for homes not on the market has hovered in the neighborhood of 7 percent. On a $450,000 home that's a $30,000 swing in either direction. On a $900,000 home in Leawood or south Overland Park, it's over $60,000. And "median" means half the estimates miss by more than that.

There are two more reasons the misses get bigger in our market specifically:

1. Basements. Johnson County homes routinely carry 800 to 1,500 square feet of finished lower level, and a walkout versus a daylight versus a full-buried basement changes value meaningfully. County records and listing feeds describe finished basement space inconsistently, and most algorithms either ignore it or treat it like above-grade space. Neither is right. I wrote about this in detail in the basement square-footage problem.

2. Micro-markets. A half-mile in Overland Park can cross a school boundary, a 1990s subdivision into a 2020s one, and a $240-per-foot street into a $300-per-foot street. My dollar-per-foot map of six Johnson County suburbs shows how wide the middle 50 percent runs inside a single city. An estimator smoothing across a ZIP code is averaging homes that no buyer would ever compare.

None of this makes the online number useless. It is a fine conversation starter and a decent trend indicator month to month. It is a poor list price.

What the county appraised value measures

Every year around March 1, the Johnson County Appraiser mails a Notice of Appraised Value. Kansas law requires that figure to represent fair market value as of January 1, so in a rising market it is, by design, already ten or eleven months stale by the time you're thinking about a fall or spring listing.

Two things sellers often get backwards:

• It is not your tax bill's basis directly. Residential property in Kansas is assessed at 11.5 percent of appraised value, then the mill levy applies. I walk through the math, with Blue Valley and Shawnee Mission examples, in my piece on Lionsgate property taxes and carrying costs.
• A low county value is not a discount buyers will expect, and a high one is not a floor. Buyers and their lenders don't price off the county. They price off recent sales. Where the county number does matter is on the buyer's side after you're under contract: if your appraised value is far below your contract price, a sharp buyer's agent will ask why, and you want an answer ready.

If your notice looks wrong, you have 30 days from the mailing date to appeal. That's a worthwhile exercise for your tax bill. It has very little to do with what you'll list for.

How a Johnson County CMA is built

Here is the actual process, because "I ran the comps" hides a lot of judgment.

Step one: pull the right comps. I'm looking for three to six homes that sold in roughly the last three to six months, as close to yours as the data allows. In an established subdivision like Nottingham Forest or Wilshire Farms, that can mean staying inside the neighborhood. In a newer community such as Sundance Ridge or Mission Ranch, it can mean reaching to a sister community by the same builder because there simply haven't been enough resales yet. Distance is a proxy for similarity, not the goal itself.

Step two: adjust each comp to your home. No comp is identical. If the comp has a three-car garage and you have two, I subtract from the comp's price. If you have the finished walkout and it doesn't, I add. The adjustments are dollar figures grounded in what the market has actually paid for that feature locally, not a national rule of thumb.

Step three: look at the pendings and actives. Sold comps tell you where the market was. Homes under contract tell you where it is heading, and active listings tell you who you'll be competing against the week you go live. A neighborhood with four actives sitting at 60 days is a different pricing problem than one with none.

Step four: weigh, don't average. The comp most like your home gets the most weight. Averaging all six treats a bad comp the same as a great one.

Step five: sanity-check per square foot. If my adjusted value implies $310 per foot on a street where everything has traded between $240 and $270, I need a reason I can say out loud to a buyer's agent. Sometimes there is one. Often there isn't.

The adjustments that move the number most here

Every market has its own set. In Johnson County, these are the ones that consistently swing a CMA by five figures:

• Lot and basement type. A walkout or daylight lot on a treed or greenbelt backing is a premium that buyers here pay for consistently. A flat lot backing to a busier road is the reverse.
• School attendance area. Blue Valley, Shawnee Mission, Olathe and De Soto boundaries run through single cities, and buyers price them. I covered how much in the school-boundary premium.
• Age of the big systems. Roof, HVAC and water heater age show up in inspection negotiations, so I price them in up front rather than giving the money back later.
• Kitchen and primary bath currency. Not every upgrade earns its cost back. My look at which builder upgrades hold value at resale applies to existing homes too.
• HOA and amenity package. Pool, clubhouse, trails and maintenance-provided lawn care each add a slice of value, and the dues that fund them subtract a slice.

From a value to a list price

A CMA gives you a value range. The list price is a strategy decision inside or near that range, and it depends on three things the comps can't tell you: your timeline, your appetite for negotiation, and what else is coming to market around you. In a tight-inventory pocket, pricing at the top of the range and holding is reasonable. With three similar homes already active, pricing just under them to be the obvious choice usually nets more in the end than starting high and chasing the market down.

It also has to survive the buyer's appraisal. A list price the comps can't support invites the problem I describe in the appraisal gap, where the deal is agreed and then the lender's appraiser disagrees. Pricing from real sales up front is the simplest way to avoid that conversation in week four.

And the value is only half of what you'll actually walk away with. Commission, title, proration and prep all come out before you see a check; my line-by-line guide to the cost of selling a house in Kansas City shows worked examples at $750,000 and $1.5 million.

Get your number

Two ways to start, depending on how much time you have:

• Quick figure now: run the free home valuation. It uses comparable-sales data to give you an estimated range in a few minutes. It is an estimate, not an appraisal, but it is built on local comps rather than a national average.
• Full CMA: contact me and I'll walk your home, pull and adjust the comps myself, and show you the pendings and actives you'd be up against. No fee and no obligation to list.

Either way, you'll come out of it knowing which of the three numbers on your screen is the real one, and why. For the rest of the process, from prep to closing day, my seller's guide picks up where this leaves off.

Tara Williams is a Johnson County, Kansas realtor with Chic Luxury Homes. Values discussed here are illustrative; a specific home's value depends on its condition, location and current market activity. Equal Housing Opportunity.