To get a real home value estimate in Sioux Falls, start with three to six closed sales from the last 90 days in your own subdivision, adjust them for square footage, finished basement, garage, and condition, then sanity-check the result against what is actually on the market right now. That is the whole method. An automated estimate is a fine place to start a conversation and a terrible place to end one — and the version most homeowners look at is the least accurate version Zillow publishes.
The number you are looking at is the weakest one
Zillow reports two separate accuracy figures: one for homes currently listed for sale, and one for homes that are not. The on-market number is dramatically better, and there is no mystery why. Once a home is listed, the model gets to see the list price, the photos, the description, and how the market is responding. Zillow says so plainly — for on-market homes the Zestimate “includes listing information such as the list price and recent market activity,” and “this information is not available when a home is off-market.”
Here is the problem. Every homeowner deciding whether to sell is, by definition, looking at the off-market number. You are checking the version of the estimate that has the least information behind it, at the exact moment you need the most.
Zillow is straightforward about the limits, to their credit. Their own documentation states the Zestimate “is not an appraisal and can’t be used in place of an appraisal,” and they explicitly encourage supplementing it with “a comparative market analysis (CMA) from a real estate agent.” You can check the current published error rates for our region on Zillow’s own accuracy page. I would rather you saw that from the source than took my word for it.
Why automated estimates struggle in Sioux Falls specifically
This line from Zillow’s documentation is the one worth reading twice: “We use data from a geographical area that is much larger than your neighborhood — up to the size of a county — to help calculate the Zestimate.”
Minnehaha County contains Sioux Falls, Brandon, Baltic, Hartford, Dell Rapids, and a lot of open ground. Lincoln County contains Harrisburg, Tea, Lennox, Canton, and the entire south-side growth corridor. A model borrowing signal across that footprint is going to smooth over exactly the differences that decide your price. Look at the spread in median price per square foot across the metro in closed sales this year: Sioux Falls $189, Brandon $191, Harrisburg $196, Tea $241. Same county lines in some cases, very different markets.
A few more things that routinely trip up an AVM on a 605-area home:
- Basement finish. County records are frequently wrong about what is finished. On a ranch with a walkout, that single field can move value by tens of thousands.
- Condition. Two identical 1996 splits on the same street, one with a new roof, HVAC, and kitchen and one original, carry the same public record and very different market values. No model has walked through either one.
- New construction. In Harrisburg, Tea, and the west side, builder homes with few closed resales nearby give the model thin comparable data to work from.
- Townhome versus single family. Our townhome and twin market sells at a median $306,500 versus $365,000 for single family — but at essentially the same price per square foot ($192 versus $190). Blend those and you get a number that describes neither.
- Lot and location micro-factors. Backing to a bike trail, siding a busy arterial, or sitting on a cul-de-sac are worth real money here and appear nowhere in a tax record.
- Acreages and unique properties. The further you get from a tract subdivision, the thinner the model’s data gets.
The five-step method you can run yourself
You do not need a license to get within a reasonable range. You need discipline about which sales you count.
1. Pull closed sales only — the last 90 days, your subdivision first
Not active listings. Not pending. Closed. An active listing tells you what a seller hoped for; a closed sale tells you what a buyer actually paid. Start inside your own subdivision, then widen to adjacent ones with similar age and build style. Do not cross the river or jump school attendance areas just to find a comp you like — that is how people talk themselves into a bad number.
If you are outside a 90-day window, widen the timeframe before you widen the geography. In a market where the City of Sioux Falls median moved 1.8% year over year (September 2026, RASE MLS), a six-month-old sale down the block is far more useful than a last-week sale two miles away.
2. Screen for genuine similarity
Match on style first (ranch to ranch, two-story to two-story), then within roughly 15% on above-grade square footage, then within about 10 years on age. Bedroom and bathroom counts, garage stalls, and lot size come next. Three well-matched comps beat ten loose ones every time.
3. Adjust, do not average
This is the step people skip, and it is the step that makes the estimate worth anything. Take each comp and adjust its sale price toward your home: add for what your home has that the comp lacks, subtract for what the comp has that you do not. The big movers in our market are finished square footage, basement finish and walkout, garage stalls, updated kitchens and baths, main-floor laundry, and mechanicals.
A word of caution on price per square foot. The median across all 1,450 closings so far this year is about $190/sqft, and that number is genuinely useful as a gut check. It is a bad primary method. A 1,200-square-foot home and a 3,200-square-foot home in the same neighborhood will not trade at the same rate per foot — smaller homes almost always carry a higher one. Use $/sqft to catch an answer that is obviously wrong, not to produce the answer.
4. Check what buyers are choosing between right now
Your competition is the set of homes a buyer would tour on the same Saturday. Pull the active listings in your price band and be honest about where yours would rank on condition and finish. City of Sioux Falls new listings ran 450 in September 2026, down 2.2% from a year ago (City of Sioux Falls, September 2026, RASE MLS). A short list of rivals supports price. It does not excuse a stale kitchen when the house next door has a new one.
5. Pressure-test the number against market behavior
Two figures tell you whether your estimate is realistic. City of Sioux Falls sellers received 97.3% of original list price in September 2026 (RASE MLS), and the median closed sale this year took 67 days to go under contract. If your number requires a buyer to pay full price in a week, it is not an estimate — it is a wish. Price where the evidence sits and the market does the rest.
What a real CMA adds that you cannot do from a laptop
Three things, honestly.
First, full MLS data. Public sites do not show you everything — concessions, days on market across relists, price-drop history, why a comp sat. That context often changes which sales are usable.
Second, someone has seen the comps. I have walked through a good share of what has sold on the south side and in the growth corridors this year. Knowing that a comp had a dated bathroom or an unpermitted finish is not a data field; it is the difference between a comp and a bad comp.
Third, the walkthrough. Condition, layout flow, deferred maintenance, and what $3,000 of paint and decluttering would actually return — none of that exists in any model. I go through the full process in How I Price Sioux Falls Homes if you want to see the mechanics.
Frequently asked questions
How accurate is Zillow in Sioux Falls?
Zillow publishes accuracy by region on its Zestimate page, and the honest answer is that accuracy varies with how much clean local data exists. What matters more than the headline number is the gap between the on-market and off-market estimates — the off-market figure, which is what you see before you list, is materially less accurate. Treat it as a starting range, not a price.
Why is my Zestimate different from my property tax assessment?
They are answering different questions on different dates. South Dakota assessors value property as of November 1 of the prior year using mass-appraisal methods; a Zestimate is a daily-refreshed model of current market value. Neither is a list price. I cover the assessment side in How Property Taxes Work in South Dakota.
Should I update my home facts on Zillow?
Yes, if they are wrong. Zillow lets owners correct square footage, bed and bath counts, and improvements, and the model incorporates those updates. If your finished basement is listed as unfinished, fixing it costs you ten minutes. It will not manufacture value that is not there, but it removes an error working against you.
How many comparable sales do I actually need?
Three to six well-matched closed sales is the working range. Below three you have no way to spot an outlier. Above six you are usually reaching into properties that are not truly comparable and diluting the answer.
Can I just use price per square foot?
As a check, yes. As the method, no. Price per square foot varies by home size, finish level, basement treatment, and submarket — Tea’s median ran $241/sqft this year against $189 in Sioux Falls. Multiplying your square footage by a neighborhood average will get you a number, and it will frequently be off by five figures.
Does a CMA cost anything?
Mine does not, and there is no obligation attached to it. If the analysis says now is a poor time for you to sell, I will tell you that.
Not a Zestimate — a real Comparative Market Analysis from a local agent who has closed 300+ homes across the Sioux Falls metro, delivered within 24 hours. Nothing to sign, no pressure, ever.
Want the comps behind your number?
If you want to see the actual closed sales your value rests on — addresses, adjustments, and the reasoning — send me your address and I will put it together. You will get the analysis whether or not you ever list. Related reading: What Is My Sioux Falls Home Worth? (2026 Value Guide), How I Price Sioux Falls Homes (The CMA Behind Your List Price), and The Best Time of Year to Sell a House in Sioux Falls.
Bryan Anfinson, REALTOR® — Hegg, REALTORS® · Sioux Falls, SD
Call or text (605) 670-9846 · bryan@hegg.com · bryananfinson.com
This article is for general informational purposes only and is not financial, legal, tax, or appraisal advice. Market figures are drawn from RASE / Sioux Empire MLS data (monthly statistics through September 2026; sold-transaction export through June 17, 2026) and describe the market generally, not any individual property. A comparative market analysis is not an appraisal. All real estate services are offered in compliance with the Fair Housing Act.
Sources
- Zillow — What is a Zestimate? (methodology, accuracy by region, and FAQ)
- RASE / Sioux Empire MLS — consolidated market statistics, City of Sioux Falls and Metro, through September 2026
- RASE / Sioux Empire MLS — sold-transaction export, 1,450 closings, January 2 – June 17, 2026