Yes. If you own a home in Jefferson County, or you are buying one, you should test for radon. Colorado is one of the highest-radon states in the country, and Jeffco sits right in the middle of it.

Why Jefferson County

Radon is a naturally occurring radioactive gas that comes from uranium breaking down in soil. You cannot see it, smell it, or taste it, and Colorado's geology produces a lot of it. It moves up through the ground and collects in the lowest levels of a home.

State health department data shows about half of Colorado homes test above the EPA action level. Jefferson County's own test results, collected by the state since 2005, track that: about half of tested homes came back at or above 4.0 pCi/L, with a county median right at 4.0.

Radon is the second leading cause of lung cancer in the US, and the leading cause among people who never smoked. It is responsible for about 21,000 deaths a year nationally.

One thing I tell every buyer: your neighbor's test tells you nothing about your house. Levels vary from house to house on the same street, and brand new homes test high too. The only way to know your number is to test.

What the number means

The EPA action level is 4.0 picocuries per liter (pCi/L). At or above 4.0, the EPA recommends fixing the home. Between 2.0 and 4.0, the EPA suggests considering it. There is no known safe level, but 4.0 is the line where action is recommended.

How a test works

A continuous radon monitor sits in the lowest lived-in level of the home for at least 48 hours, with the house closed up: windows and exterior doors shut except for normal coming and going. You get a written result the day the monitor is picked up. During a home purchase, the monitor usually goes in during the inspection and gets picked up about two days later.

If the level is high

The fix is a mitigation system: a fan and vent pipe that pull radon from beneath the foundation and exhaust it above the roofline. In Colorado these usually run about $1,000 to $2,000, install in a day, and can cut radon levels by up to 99 percent. In a purchase, sellers commonly pay for the system or credit the cost. High radon is very fixable, and it rarely kills a deal.

On an older home in the Denver metro, yes, almost always. It is a couple hundred dollars to see the one expensive system a standard home inspection cannot reach.

Why older Denver metro lines are a gamble

Most homes built before the 1980s have clay or cast iron sewer lines. Clay pipe came in short sections with a joint every few feet, and tree roots find those joints. Cast iron corrodes and scales from the inside over decades. Some mid-century homes even have Orangeburg, a compressed tar-paper pipe that deforms and fails.

Denver's older neighborhoods combine mature trees with original lines, which is exactly the combination behind most of the problems I see.

There is also the ownership question. In most Denver metro cities, the homeowner owns the sewer lateral all the way to the city main, sometimes including the section under the street. If it fails, the repair bill is yours, not the city's.

What a scope actually is

A waterproof camera on a flexible cable, fed through a cleanout from the house all the way to the city tap. It takes about 30 to 60 minutes, and the sewer scope video is always included with your report, along with a written summary of anything worth knowing.

What it finds

• Tree roots growing in through pipe joints
• Cracks and separated or shifted sections, called offsets
• Bellies, where the line sags and holds water and debris
• Corrosion and scale buildup inside cast iron
• Collapsed or failing sections
• Grease and debris blockages
• Old repairs, and what shape they are in

The math

A sewer scope typically runs $100 to $300. A full sewer line replacement in the Denver area typically runs $5,000 to $15,000 or more, depending on length, depth, and what sits on top of the line, since driveways and landscaping add to the digging.

Finding a problem before closing turns it into a negotiation: cleaning, repair, or a credit from the seller. Finding it after closing turns it into your emergency. That is the whole argument for the scope.

One honest caveat

A scope shows the line's condition on the day it is run. It cannot predict exactly how long an aging line will last. But it replaces guessing with video, and video is what you want before you sign.

A home inspection is a visual, top-to-bottom examination of the home's major systems and structure. It takes a few hours and ends with a written photo report that tells you the condition of the house before you own it.

What is covered

• Roof, flashing, and gutters
• Exterior: siding, windows, doors, grading and drainage
• Structure: foundation, crawl space, visible framing
• Electrical: panel, visible wiring, outlets, GFCI protection
• Plumbing: supply and drain lines, water heater, fixtures
• Heating and cooling: furnace, air conditioner, ductwork
• Attic: insulation, ventilation, signs of leaks or pests
• Interior: walls, ceilings, floors, stairs, windows and doors
• Built-in appliances, garage, and fireplaces where present

What is not covered

This part matters, so you know what you are and are not getting:

• The inside of the sewer line. It is buried, so that takes a separate sewer scope.
• Radon gas. That is a separate 48-hour test.
• Mold, asbestos, and lead testing, which are specialized services.
• Anything concealed behind walls, under floors, or under insulation.
• Cosmetic condition. An inspection is not a code-compliance certification or a warranty.

How long it takes

Most inspections run two and a half to four hours depending on the home's size, age, and condition. I deliver the report the same day, with photos, videos, and plain-language explanations of what matters and what does not. If you add a sewer scope, its video is always included with the report.

Should you attend? Yes, if you can

You do not need to be there the whole time. Come for the last 30 to 45 minutes and I will walk you through the findings in person, show you the main water and gas shutoffs, and answer every question you have. Buyers learn more about their house in that walkthrough than they do reading the report cold. If you cannot attend, I do the same walkthrough by phone or video.

How to read the report

Not every finding carries the same weight, and a long report does not mean a bad house. Every report separates the things that matter now, like safety issues and major defects, from ordinary maintenance and the small stuff every lived-in home has. I flag which is which, because a 60-page report full of loose doorknobs helps nobody. Start with the summary, then dig into the photos of anything that concerns you.

It is not required, but for many sellers it is money well spent, especially on an older home. A pre-listing inspection moves surprises from the middle of your negotiation to before your home ever hits the market.

What it is

The same inspection a buyer would order, done while you are still in control of the timeline.

What it changes for a seller

• You find problems on your own schedule. Fix them, price them in, or disclose them. Your choice, with no deadline pressure.
• Fewer surprises at the inspection objection deadline, which is where a lot of Colorado deals get tense or fall apart.
• Cleaner negotiations. A buyer who cannot point to a newly discovered furnace or roof problem has less room to reopen the price at the last minute.
• A report you can share with buyers up front, which builds trust and can support your asking price.

The honest tradeoffs

It costs a few hundred dollars up front.

Colorado sellers must disclose known defects. Once your own inspection documents a problem, you generally have to fix it or disclose it. Most sellers find that is a feature rather than a bug, since buyers tend to find out anyway, but go in with your eyes open.

And most buyers will still order their own inspection. That is normal. A pre-listing inspection usually means their inspection finds less to argue about.

When it makes the most sense

Older homes, homes with deferred maintenance, estate sales where the seller does not know the home's history, and any seller who wants a fast, clean transaction more than they want to gamble.

What sellers usually do with the findings

The most common pattern I see: fix the small, cheap items a buyer would trip over, like a missing GFCI outlet, a dripping faucet, or a furnace that needs service. For the bigger items, many sellers skip the repair and instead get a written quote, disclose the issue, and price accordingly. A known problem with a quote attached is far less scary to a buyer than an unknown one their inspector just found.

Yes. New does not mean problem-free. The pipe is new, but it has been through a construction site, and a scope is the only way to see how it came out the other side.

What happens to new lines during a build

Sewer lines go in early, and then months of construction happen on top of them. The problems I see on new builds are consistent:

• Construction debris washed or knocked into open lines: grout, concrete chunks, wood, and trash
• Poor or misaligned connections at couplings
• Pipe sections cracked or crushed by heavy equipment and backfill
• Bellies where the line was bedded poorly and sags, holding water
• Test caps or plugs left in the line and forgotten

None of these show up from above ground. Everything flushes fine on a walkthrough, right up until it does not.

The warranty angle

This is the part buyers miss. Most builders warranty their work for the first year, and that coverage has a clock on it. A scope inside the warranty window turns a problem into the builder's repair, not yours. The same scope after the warranty expires turns it into your bill. Many owners schedule warranty punch-list work around the 11-month mark, and that is a smart time to scope the line too.

One practical note: before closing, the builder still owns the home, so the scope needs their OK. Your agent can usually arrange that, and a builder who has nothing to hide rarely objects. Builders do occasionally push back, which is itself worth knowing.

If you are buying a new build, scope before closing if you can. If you already own one, scope before the builder's warranty runs out.

The math

A scope typically runs $100 to $300. A repair on a new home means digging up a brand new yard, and sewer replacement in the Denver area typically runs $5,000 to $15,000 or more. On a new build the line itself is rarely the problem. What construction did to it is.

And plenty of scopes on new builds find nothing but debris. Even then, getting the line cleaned and documented inside the warranty window is worth the cost, because you start ownership with a known-clean line on video. The sewer scope video is always included with the report.

Yes. A mitigation system is equipment, not a guarantee, and equipment fails. The only way to know a system is actually working is to test.

Systems fail quietly

A radon mitigation system is a fan and vent pipe that pull radon from beneath the foundation. It works well when it runs, but a few things go wrong in real houses:

• The fan dies. Fans run around the clock and typically last 5 to 10 years. When one quits, it makes no noise and leaves no puddle.
• Someone unplugs it. Painters, remodelers, and crawl-space work all lead to unplugged fans that never get plugged back in.
• Piping cracks or comes apart, usually in the attic or at a joint, and the suction path is gone.
• The home changes. Additions, finished basements, and foundation work can open new paths for radon that the original system was never designed to handle.

With the fan off, the system is just a pipe. It may vent a little passively, but you are no longer getting the protection it was installed for.

What the experts recommend

The EPA and Colorado's health department recommend retesting every two years, even in homes with a mitigation system, and again after any renovation. That recommendation exists precisely because systems drift and fail without anyone noticing.

Buying a home that already has a system

A listing that says "radon mitigation system installed" tells you a system exists. It tells you nothing about whether it is running today. Before you rely on it, test. The test is the same 48-hour monitor, run with the system operating, and it is smart to check the fan and the little gauge on the pipe first. If the gauge shows no suction, the fan is not moving air.

The good news

Testing a mitigated home is quick and inexpensive, and most of the time the result comes back low and you have real proof the system works, not just a pipe in the corner. When it does come back high, the fix is usually simple: a new fan, a reconnected pipe, or an adjustment by a mitigator.