Which Add-On Home Inspections and Tests Are Actually Worth It?
- Sean Struckmeyer
- 15 hours ago
- 8 min read
When you schedule a home inspection, you'll usually be asked whether you want to add any specialized tests, radon, a sewer scope, well testing, and so on. It's fair to wonder which of those are actually worth the money and which are just extra line items on the invoice.
The real answer is that it depends on the home. A brand-new build in a Wentzville subdivision calls for a very different set of tests than a 100-year-old home in historic St. Charles or an acreage property running on a private well out in Warren County. So instead of a one-size-fits-all checklist, here's a rundown of the add-ons worth considering, when each one earns its keep, and which we handle in-house versus hand off to a trusted specialist.
The add-on inspections most worth the money depend on the home's age, location, and systems. For older homes or lots with large trees, a sewer scope catches root intrusion and pipe damage before it becomes a costly repair. Radon testing is worth it on nearly any home, because levels vary house to house and can't be predicted from the outside or when the home was built. A termite (wood-destroying organism) inspection matters throughout the St. Louis region and is generally required on VA loans in Missouri. Homes on a private well and septic should have both water testing and a septic evaluation. Older homes may also warrant lead paint and asbestos testing and a Level 2 chimney inspection. Tech Inspect performs radon, pool and spa, sprinkler, mold surface sampling, and FHA/VA well water testing in-house, and refers sewer scope and septic to trusted local specialists.
Why isn't everything included in a standard inspection?
A standard home inspection follows the InterNACHI Standards of Practice: a visual, non-invasive review of the home's major systems. That scope is deliberate. Testing the air for radon, running a camera down a sewer line, or sampling for mold each require specialized equipment, separate standards, and in some cases a different certification, so they're offered as add-ons rather than folded into the base inspection. The upside for you is that you only pay for the tests that actually fit the home you're buying.
Is a radon test worth it?
For almost any home, yes. Radon is a colorless, odorless radioactive gas that seeps up out of the soil, and it's the second-leading cause of lung cancer in the U.S., and the leading cause among people who don't smoke. You can't see it, smell it, or predict it from the curb. Two identical-looking homes on the same street can test completely differently. That's exactly why we recommend a radon test on nearly every purchase: testing is the only way to know your number.
What we want everyone to understand is, that; not every home we test comes back high, it varies a lot. But when it does, remediation isn't cheap or instant. A mitigation system can run several thousand dollars, and getting on a remediator's schedule can take several weeks, potentially delaying closing or it'll have to be done after you take the keys. Knowing your radon level number before closing gives you room to negotiate remediation or budget for it, rather than discovering it a month after you own the place. The EPA recommends taking action at 4.0 pCi/L or higher. We test with continuous radon monitors, and a short-term test typically runs about 48 hours. Learn more about our Radon Testing Service here.
Do I need a sewer scope?
A standard inspection doesn't run a camera through the sewer lateral, the underground line that carries waste from the house to the main. For older homes, and for any lot with large mature trees, that line is where expensive trouble tends to hide: root intrusion, cracks, bellies (low spots that hold water), and outright collapses. A sewer scope sends a camera down the line so you can see its condition before you buy. Repairs and replacements here can run into the thousands, and once you close, they're yours.
We don't currently perform sewer scopes in-house, but we strongly recommend having one done on older homes, and we refer our clients to the pros at The Sewer Pros.
What about a termite / wood-destroying organism inspection?
The St. Louis region sits in termite country, and a wood-destroying organism (WDO) inspection, the report often called a "termite letter," typically on the NPMA-33 form, is generally required on VA loans in Missouri and is a smart move on any home given the local pressure. In Missouri, that formal report has to come from someone licensed as a pesticide applicator through the Missouri Department of Agriculture, which is a separate license from the home inspector license.
During your inspection, we document any visible signs of termites and the conditions that invite them. When a formal report is needed, we connect you with a properly licensed WDO inspector to produce it. More on termites in Missouri: https://www.techinspecthome.com/post/termites-in-missouri-what-st-louis-area-homeowners-and-buyers-need-to-know
Should I test the well and septic on a rural property?
If you're buying out in Warren, Lincoln, or Franklin County, there's a good chance the home runs on a private well and septic system, utilities plenty of buyers have never dealt with before. Both deserve their own evaluation.
On the well side, there are really two things to check. A well flow and pump test stresses the pump and monitors water flow and electrical draw to gauge the health of the pump and the stability of the water source; a replacement pump can easily run $4,000 or more (unfortunately, we're familiar with this home maintenance bill....), and drilling a new well can start around $20,000 and go up quickly from there, depending on how deep they have to go to find good water.
Separately, FHA and VA loans have their own well water testing requirements, and the required contaminant panels and timing vary by local health authority and lender. We perform FHA/VA well water sample testing in-house. More on FHA/VA well water testing https://www.techinspecthome.com/post/fha-va-well-water-testing-in-missouri-what-buyers-on-a-private-well-need-to-know.
For septic, we recommend bringing in a professional septic service company. They're the experts, and septic repairs are expensive, and unlike some issues, they land squarely on the homeowner, not the seller.
What add-ons matter for an older home?
Age changes the list. If a home was built before 1978, it may contain lead-based paint — federal rules banned it for residential use that year. Homes built before the 1980s can also contain asbestos in materials like floor tile, pipe wrap, insulation, and some siding. Neither is automatically an emergency; condition is what matters. But if you're planning renovations that will disturb those materials, testing tells you what you're dealing with before demo day.
If the home has a chimney, the standard inspection covers what's visible from the exterior and the roof. Industry standards (NFPA 211) recommend a Level 2 chimney inspection whenever a home changes hands, it goes beyond a visual once-over to scan the inside of the flue with a camera, and a certified chimney professional performs it. One more era-specific item: older homes that once used oil heat may have a buried oil tank. It's far less common in the St. Louis area, than natural gas or propane, but if there's any history of oil heat, an oil tank scan is worth asking about.
What about pool, spa, and sprinkler systems?
If the home has a pool or spa, an in-ground irrigation system, or you've spotted signs of moisture and want peace of mind, we can help there too. We offer pool and spa inspections, lawn sprinkler and irrigation inspections (but not backflow testing), and mold surface sampling as add-on services. None of these are part of a standard inspection, but each is straightforward to add when the property calls for it.
Which add-ons should you actually get?
Here's the quick version of what's worth considering and who typically handles it:
Add-on / test | Best suited for | Who performs it |
Radon test | Nearly every home | Tech Inspect (in-house) |
Sewer scope | Older homes; lots with large trees | Referral, The Sewer Pros |
Termite / WDO (WDIR) | Any St. Louis-area home; generally required on VA loans | Referral, licensed WDO inspector |
Well water testing (FHA/VA) | Homes on a private well; FHA/VA loans | Tech Inspect (in-house) |
Well flow / pump test | Homes on a private well | Separate service for well homes |
Septic evaluation | Homes on a septic system | Referral — septic service company |
Pool & spa | Homes with a pool or spa | Tech Inspect (in-house) |
Lawn sprinkler / irrigation | Homes with an irrigation system | Tech Inspect (in-house) |
Mold surface sampling | Musty odors or suspected mold | Tech Inspect (in-house) |
Lead paint / asbestos | Pre-1978 (lead) / pre-1980s (asbestos) homes | Specialist / lab |
Level 2 chimney | Any home with a chimney, at sale | Certified chimney professional |
Oil tank scan | Older homes with a history of oil heat | Specialist |
There's no universal checklist, the right add-ons depend on the home's age, location, and systems, plus your own budget and risk tolerance. When you schedule with us, the online scheduler lays out the available add-ons with cost and time, so you can build the inspection that fits the property. Not sure which ones make sense for a specific home? Ask us. Helping you think through exactly that is a big part of what we do.
The bottom line
The base inspection catches a lot, but the right add-ons close the gaps that cost the most to miss. Match the tests to the home, plan for the timeline, and you walk into closing with the full picture, instead of an expensive surprise a month later. Check back often on our current service offerings, as we are always working to expand our services to best support our clients.
Frequently asked questions
Which add-on inspections does Tech Inspect perform? We perform radon testing, pool and spa inspections, lawn sprinkler and irrigation inspections, mold surface sampling, and FHA/VA well water testing in-house. We refer sewer scopes to The Sewer Pros and septic evaluations to a professional septic service company, and we connect you with a licensed WDO inspector for a formal termite report.
Does a newer home need a sewer scope? It's less critical than on an older home, but a long lateral or large mature trees on the lot can still cause root intrusion and pipe problems. A sewer scope is most valuable on older homes and lots with big trees.
Does every home need a radon test? We recommend it on nearly every home. Radon levels can't be predicted from the outside and vary house to house, so testing is the only way to know. Not every home tests high, but the cost of finding out is small compared with the cost of a mitigation system.
Are add-on tests required, or optional? Most are optional and up to the buyer. A few are loan-driven, a WDO/termite inspection is generally required on VA loans in Missouri, and FHA and VA loans have well water testing requirements for homes on a private well. Confirm specifics with your lender.
How much do add-on inspections cost? Costs vary by service and by property. Our online scheduler shows current add-on pricing and the added time when you book, so you'll see exactly what each one adds before you commit.
Ready to build the right inspection for the home?
See what a Tech Inspect report looks like with three full sample reports, explore everything inside the report, or schedule your inspection — and we'll help you decide which add-ons fit the home. Curious what they cost? Our online scheduler lays out current add-on pricing and time when you book.
Tech Inspect Home Services LLC · 3580 Highway T, Marthasville, MO 63357 · 636-201-6366 · sean@techinspecthome.com
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