What does a home inspection not cover?

Stasis Home Research Every claim on this page is graded against peer-reviewed health research and linked to its primary source.Updated August 2026

A home inspection is a non-invasive, visual examination, so it excludes what needs an instrument or a laboratory. Both governing standards of practice state the inspector is not required to determine water quality, air quality, or the presence of mold or radon. Those are separate tests on separate schedules, and none is included by default.

What is a home inspection, in the standards' own words?

InterNACHI's Standards of Practice define it as a non-invasive, visual examination of the accessible areas of a residential property, performed for a fee, designed to identify defects within specific systems and components. Every word in that sentence is doing work, and three of them decide what you get.

Non-invasive means nothing is opened. No wall is cut, no finish is removed, no sealed system is taken apart. ASHI's standard makes the matching point from the other side, that the inspector is not required to determine the condition of systems and components that are not readily accessible.

Visual means the instrument is a trained pair of eyes. That covers a lot, because most building defects announce themselves visually to somebody who knows the failure patterns. It is powerless against anything with no visual signature at all.

Accessible means what can be reached on the day without dismantling the house. A crawlspace nobody can enter, an attic with no safe access, and a wall cavity are outside the examination by definition rather than by oversight.

InterNACHI's standard is also explicit that the report is based on observations made on the inspection date, and that it will not reveal every issue. That is an honest statement about what one afternoon can establish, and it is the right frame for everything below.

What is a home inspector not required to check?

Both standards exclude the same category: environmental measurement. InterNACHI's Standards of Practice §2.2 lists, among the things the inspector is not required to determine, the air quality, the presence of airborne hazards including radon, the presence of mold, mildew or fungus, and the existence of environmental hazards including lead paint, asbestos or toxic drywall.

Water is excluded in the plumbing section rather than the environmental one. InterNACHI §3.6 states the inspector is not required to determine the water quality, potability or reliability of the water supply or source. So a private well can be inspected as equipment and still tell you nothing about what comes out of it.

ASHI's standard reaches the same place in a single sentence, and it is the broadest of the two. §13.2.A.11 states the inspector is not required to determine the presence of environmental hazards including, but not limited to, allergens, toxins, carcinogens, electromagnetic radiation, noise, radioactive substances, and contaminants in building materials, soil, water, and air. Water quality is excluded again separately at §6.2.B.2.

Read those together and the boundary is clean. Two independent bodies, writing separately, both put every measured environmental question outside the standard scope of a home inspection.

One clarification that matters before you conclude anything about a particular inspector. A standard of practice is a floor, not a ceiling. Many inspectors offer radon testing, water sampling or mold assessment as add-on services, and some hold separate credentials for them. What the standards establish is that none of it is included unless somebody asks for it, which means the default is exclusion and the burden of asking is yours.

What the two governing standards of practice say a home inspector is not required to determine
Question you might assume is covered	InterNACHI Standards of Practice	ASHI Standard of Practice
Is the drinking water safe?	Not required: water quality, potability or reliability of the water supply or source (§3.6)	Not required: water quality (§6.2.B.2); contaminants in water (§13.2.A.11)
Is there radon?	Not required: the presence of airborne hazards, including radon (§2.2)	Not required: radioactive substances (§13.2.A.11)
Is there mold?	Not required: the presence of mold, mildew or fungus (§2.2)	Not required: allergens and toxins (§13.2.A.11)
What is the indoor air like?	Not required: the air quality (§2.2)	Not required: contaminants in air (§13.2.A.11)
Is there lead paint or asbestos?	Not required: environmental hazards, including lead paint, asbestos or toxic drywall (§2.2)	Not required: carcinogens and contaminants in building materials (§13.2.A.11)
What is inside the walls?	Non-invasive, visual examination of accessible areas only (§1.1)	Not required: systems and components that are not readily accessible (§13.2.A.1)

A standard of practice sets the minimum scope, not the maximum. Many inspectors offer these as separately priced add-ons, and some hold separate credentials. The point is that none is included by default, so ask before the day rather than after the report.

Why those exclusions are reasonable

Not one of these exclusions is a gap in the profession. Each excluded question needs its own instrument and its own clock, and the clock is usually the harder half. Radon is the clearest case: EPA's short-term test sits in the home for two to 90 days, and a long-term test runs more than 90, because levels vary from day to day and season to season. Nothing about that fits into an afternoon.

Fine particles have the same shape. The health-based reference from the World Health Organization is an annual average of 5 micrograms per cubic meter, and the federal standard is an annual average of 9.0. Those are numbers built out of many days of data. A single reading taken during a walkthrough cannot be compared to either, in any direction.

Water needs a laboratory rather than a schedule. The contaminants that decide whether water is safe, lead, arsenic, nitrate, and the chlorination byproducts, are measured in parts per billion, and nothing you can see, taste or smell works at that resolution. That is a sample sent to a certified lab, not an observation.

Mold is excluded for a different reason again, and it is the one worth understanding before anybody sells you a test. EPA has set no federal limit for mold or mold spores, so there is no number a result could be graded against, and EPA states that in most cases, if visible mold growth is present, sampling is unnecessary. An inspector reporting visible growth and a moisture source has given you the actionable finding already.

So the exclusions mean a home inspection is scoped, not inadequate. It answers the building questions well and leaves the measured questions to instruments that need time. The mistake is assuming the inspection covered something it never claimed to.

Which tests are worth adding, and when

Four, and their priority depends on the house rather than on a checklist. Radon is first for almost every home, because EPA recommends testing every home regardless of the local zone and states that its own Map of Radon Zones should not be used to decide whether an individual home needs testing. A recent build date is not a pass either, since a tighter envelope holds in whatever the soil emits.

Radon in a transaction has one wrinkle worth knowing. A mail-in kit is the right tool for finding out where you stand, and it stops being the right tool the moment money turns on the result. EPA's guide puts it as a choice: if you prefer, or if you are buying or selling a home, you can hire a qualified tester instead.

Water is second, and which test you need depends entirely on the supply. A home on a private well has no utility report behind it and no regulator watching it, so a certified laboratory panel is the only place the numbers come from, and the well transfers with the house. A home on a utility has a free annual Consumer Confidence Report covering the source water, and a tap test is what covers the lead its own plumbing may add.

Mold is third and conditional rather than routine. Add an assessment when there is a specific reason: visible growth, a musty smell with no source, a stain that suggests a leak, or a disclosed water event. General worry is not a reason, and the company assessing should not be the company quoting the removal.

Age decides the fourth. Lead paint and asbestos are era questions rather than condition questions, and both are named in the exclusions of both standards. If the house predates the relevant era for your state's disclosure rules, that is a separate specialist rather than an add-on to the general inspection.

The practical instruction under all four is one sentence: ask what is included before the inspection is booked, not after the report arrives. Every one of these is available, none is automatic, and the report will not tell you what was never in scope.

We are not home inspectors, and here is the line

Stasis does not perform home inspections and does not work to the InterNACHI or ASHI standards of practice. We do not evaluate structure, roof, foundation, electrical systems, or the condition of plumbing, and nothing we produce substitutes for an inspection by a qualified inspector in a real estate transaction. If you are buying a house, hire one.

What we do is the other half, the measured half those standards exclude on purpose. Water, air, light and humidity, on the instruments and the schedules each of them actually needs, interpreted against health-based levels rather than only against legal limits.

The two are complements rather than competitors, and they answer different questions. An inspector tells you whether the building is sound. A measurement tells you what is in the water, the air and the light inside it. A house can pass one and fail the other, which is exactly why the standards separate them.

One caution that applies to us as much as to anyone you hire. Ask whoever measures your home whether they also sell the fix, and ask what happens to their revenue when the answer is that nothing needs fixing. We assess and refer rather than remediate on the mold side, and where a referral carries a fee we disclose it upfront. Our own fee covers the visit rather than the finding, so a report that says nothing here needs attention is a survivable outcome for us. Apply that test in both directions.

Does a home inspection include radon or mold?

Neither is included unless you ask for it. InterNACHI's Standards of Practice list the presence of airborne hazards including radon, and the presence of mold, mildew or fungus, among the things an inspector is not required to determine. ASHI's standard covers both under environmental hazards at §13.2.A.11. Both are commonly available as add-on services and some inspectors hold separate credentials for them. The default is exclusion, so the burden of asking is yours.

Does a home inspection include water testing?

A home inspection does not include water testing by default. InterNACHI's Standards of Practice state the inspector is not required to determine the water quality, potability or reliability of the water supply or source, and ASHI's standard excludes water quality separately and again lists contaminants in water among the environmental hazards an inspector is not required to determine. Many inspectors offer water sampling as a priced add-on, so ask before booking. On a private well it matters more, because no utility report exists to fall back on.

What should be on a home inspection checklist for environmental risks?

Four items, none of them automatic. Radon, because EPA recommends testing every home and its zone map explicitly does not decide it for an individual house. Water, matched to the supply: a certified lab panel on a well, the utility report plus a tap test on a city home. Mold, only where there is a specific reason such as visible growth, a musty smell with no source, or a disclosed water event. And era hazards, lead paint and asbestos, decided by the age of the house rather than its condition.

Where do I start?

Ask what is included before you book, not after the report. Radon, water, mold and asbestos are add-ons, never defaults.
Read your inspector's standard of practice. Both InterNACHI's and ASHI's are published, and both list what is not required.
Book a radon test for almost any home. EPA recommends testing every home, and its zone map is explicitly not a substitute.
If the result will decide money in a sale, use a qualified tester rather than a mail-in kit.
Find out whether the home is on a well or a utility before deciding which water test you need. They are different questions.
On a well, book a certified laboratory panel. No utility report exists, and the well transfers with the house.
On a utility, pull the free Consumer Confidence Report for the source water and test the tap for what the pipes add.
Add a mold assessment only for a specific reason: visible growth, a musty smell with no source, a stain, or a disclosed water event.
Check your own state's rules. Home inspector licensing, and mold assessor licensing, both vary by state.

What does the science say?

AIRRadon A hazard with no smell, no symptoms and no visual signature, which is why no inspection can see it.WTRLead Why the age of the plumbing decides this and the utility's report cannot, on a house you have not lived in yet.AIRMold Why no agency publishes a spore count, and what a finding does and does not establish about a house you are buying.AIRPM2.5 (fine particulate matter) The pollutant whose main standard is an annual average, which is the clearest reason a walkthrough cannot measure air.

What actually works?

Method

Radon mitigation (sub-slab depressurization)

Method

Reverse osmosis

Common questions

What are the biggest things a home inspection misses?

The measured ones, and they are excluded by design rather than by oversight: water quality, indoor air quality, radon, mold, lead paint and asbestos are all named in both standards as things the inspector is not required to determine. Anything inside a wall is out too, because the examination is non-invasive and visual, covering accessible areas only. InterNACHI's standard also states plainly that a report is based on observations made on the inspection date and will not reveal every issue.

Is a home inspection worth it if it does not test anything?

Yes, because it answers a different question well. A home inspection is a visual examination designed to identify defects in specific systems and components, and most building defects do announce themselves visually to somebody who knows the failure patterns. What it cannot do is measure something with no visual signature, like radon, or something whose standard is an annual average, like fine particles. Treat it as scoped rather than inadequate, and add the measured tests on purpose.

Should I test the water before buying a house?

Yes, and which test depends on the supply. A home on a private well has no utility report and no regulator behind it, so a certified laboratory panel is the only source of numbers, and that responsibility transfers to you with the house. A home on a utility has a free annual Consumer Confidence Report for the source water, which stops at the curb, so a tap test is what covers the lead the home's own plumbing may add. Neither is part of a standard inspection.

Does a new construction home need an inspection and testing?

A recent build date is not a pass for the measured questions. EPA is blunt that radon turns up in old homes, new homes, drafty homes and insulated homes, and a tighter, more energy-efficient envelope holds in whatever the soil emits, so newer construction is not automatically lower. EPA also recommends testing a home built with radon-resistant features. On the building side, a new construction inspection is a separate service from a resale inspection, so ask what scope you are buying.

Who do I hire to test for radon when buying a home?

A qualified tester rather than a mail-in kit, once money turns on the result. EPA's guide frames it as a choice: if you prefer, or if you are buying or selling a home, you can hire a qualified tester. The credential to ask for is a state license, or a listing with one of the two nationally recognized proficiency programs. A state radon program is a better starting point than a search engine, because EPA requires states receiving indoor radon grants to publish lists of credentialed providers only.

Are you a home inspection company?

No. Stasis does not perform home inspections, does not work to the InterNACHI or ASHI standards of practice, and does not evaluate structure, roof, foundation, electrical systems or plumbing condition. Nothing we produce substitutes for an inspection by a qualified inspector in a real estate transaction. What we do is the measured half those standards exclude on purpose: water, air, light and humidity, on the instruments and schedules each needs, read against health-based levels rather than only legal limits.