Jeff Merrill | Sioux Falls Realtor

Radon is the one home-buying risk you can’t see, smell, or taste — and here in the Sioux Falls metro, it’s more common than a lot of buyers realize. You’ve budgeted for your down payment, your closing costs, and your inspection. Radon deserves a line in that plan too, because ignoring it is the kind of shortcut that follows you into the house.

Here’s how to think about it, what it actually costs, and how to handle it in your offer so it doesn’t blow up your closing.

Do You Need a Radon Test When Buying a Home in Sioux Falls?

Yes — you should test for radon on almost every Sioux Falls home you’re serious about buying. Minnehaha and Lincoln counties sit in EPA Radon Zone 1, where the average indoor level runs around 6 pCi/L, above the EPA’s 4.0 action level. A short-term test usually costs $150 to $250 as part of your inspection, and if the level comes back high, a mitigation system runs about $800 to $2,000 — a cost you can ask the seller to cover before closing.

Why Radon Matters More Here Than Most Places

Radon is a naturally occurring gas that seeps up from the soil and collects inside homes, usually in basements and lower levels. The EPA calls it the leading cause of lung cancer among people who don’t smoke. You won’t know it’s there without a test.

Sioux Falls sits in the highest-risk category. Both Minnehaha County and Lincoln County are classified as EPA Radon Zone 1, meaning the predicted average indoor level is above 4 pCi/L. The American Lung Association’s South Dakota data puts Minnehaha County’s mean level around 6.5 pCi/L, and user-submitted tests across Sioux Falls zip codes — including the 57108 area on the south and Harrisburg side — regularly land near 6.0 pCi/L. The EPA’s action level is 4.0.

That’s the key number to remember: 4.0 pCi/L. At or above it, the EPA recommends fixing the home.

Here’s the part that trips people up. Radon doesn’t care whether the house is a 1970s ranch in central Sioux Falls or a brand-new build in Tea. Levels vary house to house, sometimes on the same street, based on the soil, the foundation, and how the home was built. The only way to know your specific home is to test that specific home.

How Testing Works and What It Costs

You test for radon during your inspection window, right after your offer is accepted and while your inspection contingency is still active. That timing matters — it’s the leverage point that lets you do something about a bad result.

A short-term radon test runs 48 hours or so and costs $150 to $250. Most Sioux Falls home inspectors either include it or add it on, so you’re often bundling it with the general inspection, the sewer scope, and everything else you’re already paying for. The tester places a continuous monitor or a charcoal kit in the lowest livable level of the home under closed-house conditions, then reads the result in pCi/L.

If the number comes back under 4.0, most buyers move on without mitigation, though some choose to address anything above 2.0 for extra peace of mind. At 4.0 or higher, you’ll want a plan — and you’ve got options.

For a fuller picture of everything else that lands on your plate at the table, my breakdown of what it costs to sell a house in Sioux Falls walks through the seller side of those same closing numbers, which helps you understand where a mitigation credit fits in.

What Happens If the Test Comes Back High

First, don’t panic. A high radon reading in Sioux Falls is common, and it’s fixable — usually in a single day.

The standard fix is a sub-slab depressurization system: a pipe and a fan that pull radon out from under the foundation and vent it above the roofline. In the Sioux Falls area, that system runs about $800 to $2,000, and most homes with a standard basement land in the $1,000 to $1,500 range. Complex foundations, crawl spaces, or very high starting levels push you toward the top of that range.

Now the part that actually protects your wallet. Because you tested inside your inspection contingency, a high result is a negotiation, not a surprise you eat after closing. You can ask the seller to install a mitigation system before closing, credit you the cost at the table so you handle it yourself, or reduce the price. Which route makes sense depends on the market and how the rest of your deal is shaped, but the point is you have a seat at that table.

Keep in mind South Dakota’s disclosure rule here. Sellers are required to share known radon information on the Seller’s Property Condition Disclosure Statement (SDCL 43-4-44). If a prior test or an existing system shows up on that form, read it closely. But a disclosure is not a substitute for your own current test — an old reading or a blank line tells you nothing about the air in that basement today.

New construction deserves its own note. Some newer homes in the Tea, Harrisburg, and NW Sioux Falls corridor are built with a passive radon system — pipes roughed into the foundation that vent soil gas without a fan. Passive systems cut levels by roughly half, which isn’t always enough. If you’re buying new, still test after the home is finished, and budget for adding an active fan if the result comes back above 4.0. My guide on whether you need a Realtor for new construction in Sioux Falls covers how to get these details written into your builder agreement before you’re locked in.

FAQ

Is radon testing required when buying a home in South Dakota?
No. South Dakota has no law requiring a radon test or radon-resistant construction. The only rule is that sellers must disclose known radon information on the Seller’s Property Condition Disclosure Statement. Given that Sioux Falls sits in EPA Zone 1, you should test regardless — the state won’t do it for you.

What is a safe radon level in Sioux Falls?
The EPA recommends taking action at 4.0 pCi/L or higher. No level is completely risk-free, and the EPA suggests considering a fix even between 2.0 and 4.0. Below 4.0, most buyers don’t mitigate. With a Sioux Falls average near 6.0, plenty of homes here land above the action line.

How much does radon mitigation cost in Sioux Falls?
Most systems run $800 to $2,000, with the typical sub-slab basement system landing around $1,000 to $1,500. Crawl spaces, complex foundations, and very high levels cost more.

Can I ask the seller to pay for radon mitigation?
Yes. As long as you test inside your inspection contingency, you can negotiate for the seller to install a system, credit you the cost at closing, or lower the price. This is a normal ask in South Dakota deals, not a deal-breaker.

Do new construction homes in Tea and Harrisburg have radon?
They can. Some newer builds include a passive radon system that cuts levels by about half, but that’s not always enough to get below 4.0. Test after the home is finished and budget for an active fan upgrade if needed.

Ready to Buy With Your Eyes Open?

Radon is a small line item that catches a lot of Sioux Falls buyers off guard — and it’s one of the easiest things to handle when you plan for it before you write the offer. Get it tested, know your number, and use your inspection window while it’s open.

If you’re getting ready to buy in Sioux Falls, Brandon, Harrisburg, Tea, or anywhere in the metro and you want someone who’ll make sure details like this don’t slip, let’s talk. Call or text me at 605-201-2846, or start at siouxfallsgreathomes.wordpress.com.

About Jeff Merrill: Jeff Merrill leads The Jeff Merrill Team, powered by eXp Realty, serving Sioux Falls and the surrounding South Dakota communities of Brandon, Harrisburg, Tea, Madison, Mitchell, Canistota, and beyond. Jeff coaches buyers, sellers, and new agents through the real decisions that shape a deal — no hype, no hedging. Reach him at 605-201-2846.

That last part trips people up, so start here: you don’t fill out a form on a government website and wait. You get pre-approved with a lender who’s signed up to do SDHDA loans, and they run the assistance right alongside your mortgage. The whole thing moves as one file.

Let’s walk through what you actually get, whether you qualify at Sioux Falls prices, and how to use it without scaring off a seller.

What SDHDA actually offers — and what it costs you

The core of it is the First-Time Homebuyer Program: a fixed-rate first mortgage paired with optional down payment assistance. To count as a first-time buyer, you just need to have not owned your primary residence in the past three years. If you owned a home in 2021, sold it, and have rented since, you’re back in the pool.

The Down Payment Assistance piece is the part worth understanding. It’s 3% or 5% of your first mortgage amount, and it comes as a silent second mortgage — 0% interest, no monthly payment, and nothing due until you sell the home, refinance it, or pay the loan off. It isn’t a grant, so it doesn’t vanish, but it also isn’t costing you anything month to month.

Here’s what that looks like at real Sioux Falls numbers. The metro median sat around $350,500 this June, and the City of Sioux Falls proper is running about $332,500 year to date. Say you buy a townhome in Harrisburg or a starter ranch in Tea for $300,000:

• 5% assistance puts about $15,000 toward your down payment and closing costs.
• 3% assistance puts about $9,000 toward them.

For a lot of first-time buyers, that’s the entire gap between “we’re still saving” and “we’re at the closing table.” An FHA loan already lets you put down 3.5%, so pairing it with SDHDA assistance can get you into a home with very little of your own cash up front — which matters when you’re also covering an inspection, movers, and the first month in a new place.

One honest caveat, because I don’t do hype: because the assistance is a second loan, it comes off the top when you sell. If you buy at $300,000 with $15,000 in assistance and sell three years later, that $15,000 gets paid back out of your proceeds at the title company. In a market like ours — Sioux Falls prices are still climbing, up 3.9% year to date — most buyers build enough equity to cover it and then some. But you should go in knowing it’s borrowed, not gifted.

Do you qualify at Sioux Falls prices?

This is where a lot of national advice gets Sioux Falls buyers wrong. You’ll read that state programs cap out around $275,000, panic, and assume you’re priced out. That number is outdated.

The current purchase price limit for SDHDA’s First-Time Homebuyer Program is $410,000. That’s comfortably above the Sioux Falls median, so a huge share of the homes you’re actually shopping — in Harrisburg, Tea, Brandon, and across the west and northwest side — fall under the cap. If you end up buying again down the road, the Repeat Homebuyer Program raises that limit to $460,000.

There are two other boxes to check:

• Income limits. These apply and they vary by county and household size, so I won’t quote you a single number that might be stale by the time you read this. Minnehaha and Lincoln County limits are set by SDHDA and adjusted periodically. Your lender pulls the current figure for your household in about thirty seconds — ask them on the first call.
• Homebuyer education. SDHDA requires a homebuyer education course, offered online or in person through HUD-approved counseling agencies. It’s genuinely useful, and it’s a requirement, not a suggestion.

If your income lands over the limit, you’re not stuck. The Repeat Homebuyer Program and standard financing are still on the table, and there’s also the Governor’s House Program — affordable, energy-efficient two- and three-bedroom homes for income-qualified buyers — if you’re open to that path.

How to use it without losing the house

Getting the money is the easy part. Using it in a competitive offer is where a good agent earns their keep, because Sioux Falls is still a seller’s market — inventory’s down roughly 30% year over year, and well-priced homes move fast.

Start with the lender, not the listings. Get fully pre-approved on an SDHDA loan before you tour anything. When your pre-approval letter already reflects the assistance, your offer looks like any other financed offer to the seller — clean and ready. If you spring the program on everyone after you’re under contract, you risk delays that make a seller nervous.

Second, give yourself a little more time in the contract. SDHDA loans have a few extra moving parts than a plain conventional loan, so build a realistic closing timeline — often 35 to 45 days — into your offer instead of promising a two-week close you can’t hit. In this market, certainty is worth more to a seller than speed you can’t deliver.

Third, watch how you handle new construction. Builders in Tea and Harrisburg — Allen Homes, Van Buskirk, and others — sometimes push their own preferred lender with an incentive attached. That’s fine to compare, but their lender may not offer SDHDA assistance. Run both side by side. Sometimes the builder’s rate buydown beats the state assistance; sometimes the SDHDA route keeps thousands more in your pocket. If you’re weighing a brand-new home at all, my guide to using a Realtor on new construction in Sioux Falls walks through how representation and incentives actually work.

Finally, remember the local mechanics. In South Dakota, your closing happens at a title company, not through an escrow agent like some other states. You’ll review the Seller’s Property Condition Disclosure Statement before you’re locked in. And your property taxes get folded into your monthly payment through escrow — worth budgeting for early, because they’re a real line item on a Sioux Falls home.

Frequently asked questions

Do I have to be a first-time buyer to get SDHDA down payment assistance?
For the First-Time Homebuyer Program, you need to have not owned your primary home in the past three years — so plenty of “second-time” buyers still qualify. If you’ve owned more recently, the Repeat Homebuyer Program offers competitive rates and its own assistance, with a higher $460,000 purchase price cap.

Is the down payment assistance a grant I never pay back?
No. It’s a second mortgage at 0% interest with no monthly payment. You repay it when you sell, refinance, or pay off the home. You won’t feel it month to month, but it does come off your proceeds at closing when you eventually sell.

What’s the maximum price home I can buy with the program in Sioux Falls?
The First-Time Homebuyer Program caps the purchase price at $410,000, which covers most homes in Harrisburg, Tea, Brandon, and Sioux Falls proper. The Repeat Homebuyer Program goes up to $460,000.

How do I actually apply?
You apply through an SDHDA-approved lender, not the state directly. Get pre-approved first, complete the required homebuyer education course, and your lender runs the assistance alongside your mortgage as one file. You can find participating lenders at sdhousing.org or by calling SDHDA at 605-773-3181.

Can I use SDHDA assistance on a new-construction home in Tea or Harrisburg?
Often, yes, as long as the home and your income fall within the limits. Just compare the SDHDA route against any builder’s preferred-lender incentive — they don’t always offer the same programs, and the math can go either way.

Ready to run your numbers?

If you’re renting in Sioux Falls and wondering whether you’re closer to buying than you think, the fastest way to find out is a fifteen-minute conversation. I’ll point you to an SDHDA-approved lender, we’ll check your price range against the program limits, and you’ll know where you actually stand — no pressure, no pitch.

Call or text me, Jeff Merrill, at 605-201-2846, or reach out through siouxfallsgreathomes.wordpress.com. Let’s figure out your first move.

About Jeff Merrill: Jeff Merrill leads The Jeff Merrill Team, powered by eXp Realty, serving Sioux Falls and the surrounding South Dakota communities of Brandon, Harrisburg, Tea, Madison, Mitchell, Canistota, and beyond. Jeff brings a direct, no-nonsense approach to helping buyers, sellers, and new agents make confident moves in the Sioux Falls market.

Yes — you want your own agent, and you want them registered before your first model home visit. In Sioux Falls, Tea, and Harrisburg, the builder’s on-site salesperson works for the builder, not for you. Bringing your own agent costs you nothing in almost every case because the builder pays that commission, but if you tour and register alone first, most builders will refuse to add your agent later. That one visit can quietly cost you representation on a $400,000 purchase.

By Jeff Merrill | July 22, 2026

If you’ve driven the new construction corridors out past Tea, through Harrisburg, or across the northwest side of Sioux Falls lately, you’ve seen the “Model Open” flags. Inventory is up, builders are motivated, and the incentives are the best they’ve been in five years.

So you do the natural thing. You pull in, walk the model, and the friendly person at the desk hands you a card and a floor plan. They’re helpful. They’re knowledgeable. They answer every question.

Here’s what nobody tells you at that desk: that person represents the builder. Their job is to sell you that home at the highest price with the most upgrades — and to do it without you having anyone in your corner. The moment you sign in on your own, you may have already given up your right to bring in your own agent later.

Let me walk you through how this actually works in the Sioux Falls market, because the rules changed in 2025, and a lot of buyers are getting burned by information that’s a few years out of date.

The builder’s rep is not your agent

The person in the model home is called the on-site sales agent, and they are paid by the builder — Allen Homes, Van Buskirk, Cordes, Epcon, whoever it is. They are good at their job. That’s the problem.

Everything they tell you is true. It’s also curated. They’ll show you the base price, then the upgrade sheet, then the “if you sign this month” incentive. What they won’t do is tell you which upgrades hold their value in a Harrisburg resale, which lots have drainage issues you’ll pay for later, or how this builder’s actual delivery timelines compare to what they’re promising you.

That’s not dishonesty. That’s just the difference between someone who works for the seller and someone who works for you.

Your own agent does the things the builder’s rep never will:

• Compare the builder’s price to recent closed sales of similar new and resale homes in the same submarket
• Read the builder’s contract, which is written by the builder’s attorney to protect the builder
• Push back on upgrade pricing and negotiate incentives you didn’t know were on the table
• Flag construction and lot issues at framing and final walkthrough, before you sign off
• Keep your earnest money protected and your financing contingency intact

In South Dakota you’re also dealing with a Seller’s Property Condition Disclosure Statement, the transfer fee, and a title company closing rather than an escrow company. New construction has its own wrinkles on all three, and the builder’s rep isn’t going to coach you through the parts that favor you.

The first-visit rule that costs buyers their representation

This is the single most important thing in this whole post, so read it twice.

Most builders require your agent to be present, or at least registered, on your very first visit. If you walk into the model alone and put your name on the sign-in sheet, many builders will treat that as you registering yourself — and they will not add your agent to the deal afterward.

The logic is simple from the builder’s side. If you found the home on your own, the builder doesn’t want to pay a buyer’s agent commission on a sale they’d have made anyway. So they set a rule: no agent at first contact, no agent commission, no agent.

You lose your advocate over a Saturday afternoon drive-by.

The fix costs you nothing. Before you tour a single model in Tea, Harrisburg, or northwest Sioux Falls:

1. Line up your agent first, even if you’re just starting to look
2. Have your agent register you with the builder, or bring them to the first showing
3. If you’re driving by on a whim and want to peek inside, tell the on-site rep you’re working with an agent and give them your agent’s name before you sign anything

That’s it. Do that, and you keep representation. Skip it, and you may be on your own for a six-figure purchase with a contract written by the other side.

Who actually pays for your agent

The most common reason buyers skip their own agent is a myth: that it’ll cost them money. In new construction, it almost never does.

Builders pay buyer-agent commissions out of their marketing budget — typically in the 2 to 3 percent range. It’s baked into the sales structure. When you bring your own agent, you’re using a service the builder has already priced in. When you don’t, the builder simply keeps that money. You don’t get a discount for going alone.

Now, one honest qualifier, because 2026 is different from a few years ago. After the national commission rules changed in 2024 and 2025, buyers and agents now sign a written agreement about compensation before touring homes. Some builders used that shift to restructure what they pay buyer’s agents, so the amount can vary from builder to builder — and sometimes between two communities from the same builder.

What that means for you: it’s more important than ever to get the compensation spelled out up front. A good agent handles this in the buyer agency agreement before you ever set foot in a model, so there are no surprises and no out-of-pocket cost lands on you at closing. This is exactly the kind of thing I walk clients through before we tour anything.

What this looks like in the Sioux Falls market right now

The reason this matters so much in 2026 is that we’re in a buyer-favorable new construction market for the first time in years.

Builders across Sioux Falls, Tea, Harrisburg, and Brandon are sitting on more finished and to-be-built inventory than they’ve had in a long time. To move it, they’re offering rate buydowns, closing cost credits, and price reductions — some homes have come down 10 to 13 percent from the peak. Industry data shows the majority of move-in-ready new homes right now carry some kind of builder incentive.

That’s a lot of money on the table. And the person best positioned to know which of those incentives is real, which is a gimmick, and which can be pushed further is an agent who works for you — not the one whose paycheck depends on the builder’s bottom line.

A rate buydown that saves you $250 a month is often worth more than a $10,000 price cut. Knowing which lever to pull, and how hard, is the whole game. That’s not something you want to figure out alone at the sales desk.

Frequently Asked Questions

Is it cheaper to buy new construction without a realtor in Sioux Falls?
No. Builders pay the buyer’s agent commission from their marketing budget, and they don’t lower the price if you come without an agent — they just keep that money. Going alone gives you no discount and no advocate.

Can I bring my own agent after I’ve already visited the model home?
Usually not. Most Sioux Falls-area builders require your agent to be registered on your first visit. If you toured and signed in alone, most builders will refuse to add your agent to the transaction later. Register your agent before your first visit to protect your representation.

Does the builder’s sales agent represent me?
No. The on-site salesperson is paid by and works for the builder. Their job is to sell the home at the highest price with the most upgrades. They cannot negotiate against their own employer on your behalf.

Do I still need an inspection on a brand-new home?
Yes. New construction can and does have defects — drainage, framing, mechanical, and finish issues that surface at the walkthrough or in the first year. Your agent can help you schedule an independent inspection and use the builder’s warranty period correctly.

How does the 2026 buyer agency agreement affect new construction?
Buyers and agents now sign a written compensation agreement before touring. For new construction, this means getting the builder’s buyer-agent commission confirmed up front, so you know there’s no out-of-pocket cost to you before you tour a single model.

The bottom line

Buying new construction in Sioux Falls without your own agent doesn’t save you money — it just removes the one person whose only job is to protect your side of a six-figure deal written entirely by the builder. The catch is timing: line up and register your agent before your first model visit, or you may forfeit that protection entirely.

If you’re starting to tour models out in Tea, Harrisburg, or northwest Sioux Falls, get your representation in place first. I’m happy to walk you through the builders, the incentives, and the fine print before you ever sign in. Call or text me at 605-201-2846, or reach out at siouxfallsgreathomes.wordpress.com.

About Jeff Merrill
Jeff Merrill leads The Jeff Merrill Team, powered by eXp Realty, serving Sioux Falls and the surrounding South Dakota communities of Madison, Mitchell, Canistota, and beyond. He helps motivated buyers, sellers, and new agents cut through the hype in real estate with honest guidance, hands-on mentorship, and a track record of real results.