The only way to know whether a Rockford house has a radon problem is to test the air inside it, and the number that matters is 4.0 picocuries per liter. You cannot see radon, smell it or taste it, and a clean-looking basement tells you nothing. Illinois does not require a seller to test before a sale, so the decision usually belongs to you as the buyer. Here is how to make it, how a proper real estate test works, and what happens if the number comes back high.

Gambino Realtors has helped people buy and sell in Rockford since 1923, and radon is one of the few hazards that costs very little to check and can be fixed for a known price. If you are looking at homes for sale in Rockford, put radon on your list next to the roof and the furnace.

Here is the position a Rockford broker takes. Treat a radon test as a standard line in every Rockford offer, ordered the same week as the general inspection, run by a tester on the state's licensed list, and covering every lowest living area in the house. Do not wait for the seller to raise it, and do not let a clean-looking basement talk you out of it. The rest of this guide explains why, using Illinois law and the City of Rockford's own housing numbers.

What Radon Is, And What Illinois Law Makes A Seller Do

Radon is a radioactive gas. It forms when uranium that occurs naturally in soil and rock breaks down. It rises through the ground and mixes into the outdoor air, where it thins out to nothing. Inside a building, it can collect. The Illinois Emergency Management Agency, which runs the state radon program, points out that the health effect is lung cancer, and that lung cancer does not show up right away. A person can breathe radon for many years without any hint that it is in the house.

The federal action level is 4.0 picocuries per liter of air, written as 4.0 pCi/L. The Illinois radon program and the U.S. Environmental Protection Agency both recommend that you reduce the radon in a home when the level is 4.0 or higher. The state's own materials estimate the risk of lung cancer death at that level at about 7 per 1,000 people. Not everyone who is exposed gets lung cancer, and no one can predict a single person's risk. That is the honest way to say it, and it is also why the guidance is to test and treat, not to guess.

The Illinois Department of Public Health adds three facts that matter to a buyer. The first is that the gas reaches a house through small openings in the foundation, including floor drains, sump pits, crawl spaces, cracks in the floor or wall, and gaps around pipes and wires. The second is that the foundation style makes no difference, because radon has been measured in buildings with every kind. The third is that basements tend to show the highest readings, since a basement is closest to the ground. The department also notes that central and northern Illinois have been shown to have higher radon levels in soil. Rockford is in northern Illinois. It cites a state study in which 41 percent of Illinois homes tested had levels above 4.0 pCi/L. The study is undated, so treat that number as a general warning and not as a forecast for any one street.

The state also keeps a map of radon measurements by county and ZIP code, built from reports that licensed testers send in. It is worth looking at, and the agency attaches a warning to it. The map is not meant to decide whether a given house should be tested. Homes with high radon have been found throughout Illinois, and the state's position is that all homes should be tested regardless of location. A low reading on a neighbor's house does not clear yours. Radon levels can differ between two houses on the same block, because the soil under each foundation, the cracks in each slab and the way each house moves air are different.

Rockford's housing stock is the reason this matters here. The City of Rockford's Housing Needs Analysis and Market Study, which began in fall 2023, counted 44,024 residential parcels with structures built in known years. Of those, 5,405 were built from 1900 to 1919, 8,445 from 1920 to 1939, and 13,097 from 1940 to 1959. Add those together with the 2 parcels built before 1900, and about 26,949 of the 44,024, roughly 61 percent, date from 1959 or earlier. Another 9,549 were built from 1960 to 1979, 5,205 from 1980 to 1999, and 2,321 from 2000 to 2023. A further 5,429 parcels have no known build year and are left out of those counts. The study does not say how many of these homes have basements, and we could not find an official count, so we will not guess at one.

What the age figures do tell you is what you are likely to walk into. The Illinois Department of Public Health lists the ways radon gets into a house: floor drains, sump pits, crawl spaces, cracks in a floor or wall, and gaps around pipes and wires. A Rockford house from the 1920s, 1940s or 1950s has had many decades for pipes to be added, floors to be patched and drains to be put in. No source we trust says that age makes a reading higher, and the state says foundation style makes no difference. The point is narrower. You cannot judge any one of these houses by its age or its looks, and with six out of ten Rockford homes built before 1960, most of the houses you tour will have a lot of that history under the floor.

Now the legal side. Illinois has two laws that bring radon into a sale. One is the Illinois Radon Awareness Act. The other is the Residential Real Property Disclosure Act, whose seller report asks directly, on question 15, whether the seller is aware of unsafe concentrations of radon on the premises.

Under the Radon Awareness Act, a seller of residential property with one to four units must give the buyer two things before the buyer is bound by a contract. The first is the IEMA pamphlet called "Radon Testing Guidelines for Real Estate Transactions." The second is a standard form called the Illinois Disclosure of Information on Radon Hazards. The form carries a warning that every property may present a risk of dangerous radon, and it tells the buyer that IEMA strongly recommends all homebuyers have an indoor radon test before buying or taking occupancy. The seller then states one of the following. High radon concentrations are known to be present. The seller has given the buyer the most current records and reports about high radon. The seller has no knowledge of it, or earlier high levels were mitigated. Or the seller has no records or reports. The seller must also hand over any radon test results in the seller's possession that show high levels. If all of this comes after the buyer has already made an offer, the seller has to complete it before accepting that offer, so the buyer can review the material and possibly change the offer.

Read the limit of this law carefully. It requires disclosure. It does not require the seller to test the house or to fix a problem. A seller who has never tested and knows nothing can truthfully check the box saying so. IEMA says the same thing in its real estate pamphlet. It notes that many lenders and relocation companies ask for a radon test, and that the law does not, and it cautions sellers and agents to err on the side of full disclosure of material facts before a purchase agreement is signed.

The Radon Awareness Act also has exclusions. Court-ordered transfers, transfers by a lender that took a house through foreclosure, estate and trust transfers, transfers between co-owners, inheritances, sales to a spouse or close relative, and transfers to or from a government body are all outside it. So is any dwelling unit on the third story or higher above ground level. If you are buying a foreclosed home or an estate sale, nobody may hand you a radon form. Order the test yourself.

Testing During A Purchase: How A Proper Test Works

Whichever of the homes for sale in Rockford you choose, the test works the same way. A real estate transaction is a bad place for a casual test. Several parties have money riding on the result, so the U.S. EPA created special protocols for testing during a sale, and IEMA adapted them to Illinois rules. IEMA recommends professional testing in a sale, and it states plainly that it is not in the best interest of the buyer or the seller to rely on a measurement taken by anyone other than a licensed measurement professional or technician. Radon testers and fixers in Illinois are licensed by IEMA under the Radon Industry Licensing Act.

The licensing rule is plain. Section 25 of that Act says that no person may perform a service for compensation to detect radon in the indoor air, or to reduce it, unless IEMA has licensed that person. The rule that carries out the Act is 32 Illinois Administrative Code 422. The same Act says the tester must report the results to the client within 45 days of the test. In a sale you will want them in a few days, so ask for the report date before you book.

Finding a licensed tester takes a few minutes. IEMA keeps a Radon Active Licensee Listing online, and its search can be narrowed by employer, license type, service county or city. Winnebago and Boone are both on the county list, so a Rockford buyer can look for testers who serve Winnebago County and then check that the name on the company's quote matches a name on the list. Some home inspectors also hold a radon license. If yours does, ask for the license number and confirm it. If you would rather speak to a person, the state radon information line is 1-800-325-1245.

There are two accepted ways to run a real estate test. The first is two short-term tests running at the same time, each lasting 48 hours or longer, with two detectors placed four inches apart in each of the lowest areas of the home that are suitable for living in. The test calls for fixing the house if the average of the two readings is 4 pCi/L or higher. The second is a continuous monitor, a device that records radon every hour, run for 48 hours or longer in each of the lowest areas. If its average is 4 pCi/L or higher, fix the house. Short-term tests can last from two to 90 days, but most last two to seven days, and the long ones are usually impractical when a closing date is on the calendar.

The words "each of the lowest areas" carry the weight in that guidance. If a house has a basement and also a section over a crawl space, or a basement and an addition on a slab, the home has more than one foundation type, and the test has to cover each one. IEMA's guidance is that results from different areas, such as a basement and a room over a crawl space, are reported as two separate results, each independent of the other. You can only average two results that were placed at the same time in the same spot. If any one of the lowest areas is high, the advice is to fix the house. This catches people who assume a single basement reading speaks for the whole building.

In a Rockford house, that means walking the lowest level before you book the test and telling the tester what you see. Is there a finished basement, an unfinished one, a crawl space, a room added on a slab? Each lowest area that could be lived in gets its own detectors. If you tested only the basement, a clean report would say nothing about the rest of the house.

The conditions of the test matter as much as the device. For any test shorter than a week, the house has to be in what IEMA calls closed-house conditions. Windows stay shut, outside doors stay closed except for normal coming and going, and no fans that pull air in from outside may run. The closed-house period begins at least 12 hours before the test and continues through the whole test. The heating or cooling system runs normally, but only air conditioners that recirculate indoor air should run during a short test. A licensed professional posts a Radon Measurement in Progress notice at every entrance, and interfering with a test is illegal in Illinois. Opening windows on a mild day to air the house out can ruin the result. Tell the seller the test dates in writing so nobody does it by habit.

Placement is another place tests go wrong. The detector goes in the lowest area that could be used as living space, even if the current owner uses it only for storage, as long as it could be lived in without renovation. It does not go in the kitchen, the laundry room or a bathroom, because fans and humidity can throw off some detectors. It does not go inside a crawl space, on a crack in the floor or wall, or right beside a sump pump, because those spots can produce a false high reading. It should sit at least three feet from exterior doors and windows, at least one foot from exterior walls, and between 20 inches and six feet above the floor. Keep it away from drafts, direct sunlight, high humidity and heat sources like fireplaces and furnaces. A licensed tester knows all of this. If you do your own screening test with a kit, follow the same list.

If the two readings do not agree, or you cannot tell whether they agree, IEMA says to contact its Radon Program or your licensed measurement professional before drawing a conclusion. A mismatch is a reason to ask a question, not to pick the better number.

Here is how the timing works in a Rockford purchase. Under the Radon Awareness Act, the seller of a one-to-four unit home has to hand you the IEMA pamphlet and the radon disclosure form before you are obligated under any contract. If that happens after you have made an offer, the seller has to finish it before accepting your offer, and you have the chance to review it and possibly amend the offer. So in practice, ask the listing agent for the radon form before you write the offer, and read which box the seller checked. If the seller states that high radon is known, you will also be given the records the seller has.

The test itself takes at least 48 hours plus the 12-hour closed-house period before it, and then the monitor or lab result has to be read. That is the part that has to fit inside your contract. The deadlines for inspections and for asking the seller to make repairs come from the signed purchase contract, and we could not find an official source for a standard number of days, so read yours rather than trusting anyone's memory of a typical figure. Our advice is to book the radon tester on the same day you book the general home inspection, and to ask the tester for the date the report will arrive. Make the radon result a condition you can act on, not a surprise after your window has closed. A buyer whose result arrives late has lost the easy options, which are asking for a system before closing or asking for a credit.

If The Number Is High: Mitigation Basics And What To Ask For

A reading at or above 4 pCi/L is a problem that can be solved. IEMA says high radon can be reduced by a qualified, licensed radon mitigator, and that the most common technique is sub-slab depressurization. A pipe goes through the floor slab into the gravel or soil beneath it. A fan draws the radon from under the house and sends it up and out through a vent. It does not need major renovation. Where a house has an exposed dirt or rock crawl space, a similar method called sub-membrane depressurization lays a heavy plastic sheet over the soil and draws the gas from beneath it.

The state's rules about how a system must be built are specific, and they tell you what to ask a contractor. A system must reduce radon effectively, be permanently installed, run quietly and efficiently, include an indicator that shows whether the system is working, have its main suction point separate from the sump pit, and use sealed covers on sump pits with an observation port. The vent must discharge above the highest eave of the roof. That placement keeps the exhaust from drifting back through a window and away from people in the yard. IEMA also says sealing cracks alone has not been shown to lower radon significantly or consistently. A contractor who offers to caulk the basement and call it done is selling something the state does not endorse.

Money is the question every buyer asks. IEMA's current guidance says an active mitigation system typically costs between $1,000 and $1,500 to install, with the fan adding around $100 a year in electricity. The Illinois Department of Public Health gives a range of $800 to $1,200. The figures differ because they come from different publications and different years, so treat both as a ballpark and get written quotes. IEMA suggests asking for estimates from two or three licensed mitigation professionals, and it warns that a homeowner who installs a system without the right equipment or knowledge can actually raise radon levels or create other hazards. The state radon program will give you names of licensed professionals at 1-800-325-1245.

How the cost gets split is a negotiation. The law is silent on it, because the law does not require anyone to test or fix. A buyer whose test comes back high has the usual choices. Ask the seller to install a system before closing, ask for a credit toward the cost, or walk away if the contract gives you that right. A tidy way to do it is to get the licensed mitigator's written estimate first, then put a specific request in front of the seller based on that number. Keep the request inside the deadlines in your contract.

Whatever you decide, test again after a system goes in. IEMA is blunt about it: always perform a post-mitigation test. The follow-up is an independent short-term test, run while the system operates, to confirm that it is doing its job. A system without a second test is a guess. If you buy a house where the seller already installed a system, ask for the installer's name, the date, and the result of any test taken afterward. The seller's radon form has a line for exactly that, where the seller says earlier high levels were mitigated.

New houses need a note of their own. Since June 2013, Illinois has required passive radon reduction techniques in new construction, which means a vent pipe set up in the slab without a fan. IEMA warns that these passive and skeletal systems may or may not bring a home below the action level. If a new house tests at 4 pCi/L or above, the passive system should be converted to an active one with a fan by a licensed professional. New does not mean tested.

Last, think about how long you will live in the house. The EPA, according to the Illinois Department of Public Health, recommends testing a home every two years. A good reading on the day you bought is a snapshot. Soil settles, foundations crack, and a finished basement changes how air moves. A cheap test kit every couple of years is an ordinary part of owning a house in this part of the country.

Bottom Line

Test every house you plan to buy, and have a licensed professional do it. Insist on a test in each of the lowest living areas, with the house held in closed-house conditions for at least 12 hours before and throughout. Treat 4.0 pCi/L as the line, and remember that a single high area is enough to act. Expect the fix to be a vent pipe and a fan that a licensed mitigator installs, at a cost you can find out in writing before you commit, and test again afterward.

In Rockford, where about 61 percent of the homes with a known build year date from 1959 or earlier, do not lean on a house's age or appearance either way. Do not count on the seller to bring radon up. The law requires disclosure of what the seller knows and the radon pamphlet and form, and nothing more. If the sale is a foreclosure, an estate or a condo above the second floor, you may receive no radon paperwork at all. A radon test is a small cost next to a house you will live in for years. When you are ready to compare homes for sale in Rockford, add the test to your offer, and ask for the seller's radon form before you write it. For the wider picture of buying in Illinois, the Illinois Real Estate Guide gathers our articles in one place.

Radon raises the same handful of questions again and again, so here are quick answers to the ones buyers ask most.

Frequently Asked Questions