A triage instrument, and the definition that says so
Most disappointment with home inspections comes from mismatched expectation rather than bad inspecting. A buyer expects a comprehensive assessment and receives a limited, non-invasive, visual examination of readily accessible installed systems, performed in a few hours by one generalist. Both dominant standards documents in the United States — the ASHI Standard of Practice and the InterNACHI Standards of Practice — are unusually explicit about the second thing, and the explicitness lives in the exclusion lists rather than in anyone's marketing.
The right mental model is triage. The general inspection is designed to find conditions that warrant a specialist and refer them out; it is not designed to resolve them. A report that says "recommend evaluation by a licensed structural engineer" has done exactly what the standard contemplates.
InterNACHI 1.1 defines the product: a home inspection is "a non-invasive, visual examination of the accessible areas of a residential property ... performed for a fee, which is designed to identify defects within specific systems and components defined by these Standards that are both observed and deemed material by the inspector." InterNACHI 1.2 sets the threshold — a material defect is one "that may have a significant, adverse impact on the value of the property, or that poses an unreasonable risk to people."
Four qualifiers there do most of the excluding before any exclusion list is reached. Non-invasive rules out opening walls. Visual rules out anything concealed. Accessible areas rules out whatever cannot be safely reached. And deemed material by the inspector writes the inspector's own judgment into the standard, which is why two competent inspectors can produce materially different reports on the same house without either being wrong.
ASHI Section 13, part one: the general limitations
ASHI's standard runs to fourteen numbered sections, ten of which cover systems using the same two-part shape: an "X.1 The inspector shall" block followed by an "X.2 The inspector is NOT required to" block. Section 13 adds limitations and exclusions applying across all of them. A version note matters: the current ASHI standard carries an effective date of March 1, 2014, while older copies circulating on inspector websites are the January 1, 2000 edition, whose section 13 is numbered differently. References here follow the 2014 edition.
ASHI 13.1 sets the ground rules. The inspector is not required to perform actions, make determinations or make recommendations not specifically stated in the standard. Inspections under it "are not technically exhaustive" and are not required to identify or report "concealed conditions, latent defects, consequential damages" or "cosmetic imperfections that do not significantly affect a component's performance of its intended function." The standard applies to "buildings with four or fewer dwelling units and their attached and detached garages and carports," and does not limit inspectors from meeting state licensing requirements.
The phrase to sit with is not technically exhaustive. That is the standard's own summary of itself, and it means the document you receive is a screening instrument by design rather than by accident.
ASHI 13.2: the six general exclusions
The general exclusions are organized by verb, which is useful once noticed. The inspector is not required to determine, to offer, to operate, to enter, to inspect, or to do a residual list of things.
- A. Not required to determine: the condition of inaccessible systems and components; remaining life expectancy; strength, adequacy, effectiveness and efficiency; causes of conditions and deficiencies; methods, materials and costs of corrections; "future conditions including but not limited to failure of systems and components"; suitability of the property for specialized uses.
- B. Not required to offer: services contrary to law or regulation; architectural, engineering, contracting or surveying services; trades or professional services beyond home inspection; or warranties or guarantees.
- C. Not required to operate: shut-down or inoperable systems; systems not responding to normal controls; shut-off and manual stop valves; automatic safety controls.
- D. Not required to enter: areas deemed dangerous to the inspector or the property; inaccessible under-floor crawlspaces and attics.
- E. Not required to inspect: underground items and storage tanks; uninstalled items; decorative items; items in areas not entered; detached structures other than garages and carports; common elements in multiunit housing; every similar component occurrence; outdoor cooking appliances.
- F. Not required to: perform dangerous procedures; move personal property, furniture, equipment, plants, soil, snow, ice and debris; dismantle systems except as required; ignite or extinguish fires and pilot lights; probe surfaces without visible deterioration; assess code compliance; determine market value or marketability; advise on the advisability of purchase; identify hazardous plants, animals, molds or life forms; identify environmental hazards including allergens, toxins and carcinogens; determine operating costs; assess acoustical properties; evaluate soil conditions for geotechnical or hydrologic purposes; determine whether items are subject to recalls or litigation.
Two entries deserve pulling out. E.7, "every similar component occurrence," is the representative-number rule and the most under-explained sentence in the standard: the inspector need not test every receptacle, open every window or run every faucet. A report is a sample, not a census. And F.16 is worth quoting to anyone buying on expansive clay, fill or a hillside — soil evaluation belongs to a geotechnical engineer and is expressly outside the standard.
InterNACHI Section 2: limitations, exceptions and exclusions
Section 2.1 lists ten limitations. An inspection is not technically exhaustive; will not identify concealed or latent defects; will not deal with aesthetic concerns or matters of taste; will not determine the suitability of the property for any use; does not determine market value or marketability; does not determine the insurability of the property; does not determine the advisability or inadvisability of the purchase; does not determine life expectancy of the property or any component; does not include items not permanently installed; and applies to properties with four or fewer residential units and their attached garages and carports.
Section 2.2 divides the exclusions into three parts. Part I — things the inspector is not required to determine — is the longest and most consequential: property boundary lines or encroachments; the condition of anything not readily accessible; service life expectancy; size, capacity, BTU, performance or efficiency; the cause of any condition or of the need for repair; future conditions; compliance with codes or regulations; evidence of rodents, birds, bats, animals, insects or other pests; the presence of mold, mildew or fungus; airborne hazards, including radon; air quality; environmental hazards, including lead paint, asbestos or toxic drywall; electromagnetic fields; hazardous waste conditions; manufacturers' recalls; acoustical properties; correction, replacement or repair cost estimates; and operating cost estimates.
Part II — not required to operate — covers any system that is shut down or does not function properly; low-voltage systems including phone, cable and satellite; anything that does not turn on with normal controls; shut-off and manual stop valves; electrical disconnects and overcurrent devices; alarm systems; and moisture meters and gas detectors.
Part III, the residual list, is where the practical exclusions live: move personal items or obstructions; dismantle, open or uncover components; enter areas deemed unsafe or not readily accessible, including crawl spaces; inspect underground items including irrigation systems and storage tanks; perform any unsafe act, including walking a roof, climbing a ladder or entering an attic; inspect decorative items, common elements in multi-unit housing, or intercom, speaker and security systems; offer guarantees or warranties; provide engineering services; perform any trade or professional service other than home inspection; research property history; determine construction age or distinguish original from added components; determine insurability; perform Phase 1 or environmental audits; or inspect systems not included in the standards.
The per-system carve-outs that produce the most surprise
Beneath the general exclusions, each system section carries its own "not required to" block. These generate the most post-closing shock.
Roof. InterNACHI requires inspection of "the roof-covering materials; the gutters; the downspouts; the vents, flashing, skylights, chimney, and other roof penetrations," but does not require the inspector to "walk on any roof surface," to "predict the service life expectancy," or to "remove snow, ice, debris or other conditions that prohibit the observation of the roof surfaces." A roof read from the ground, a ladder at the eave, or binoculars is fully compliant; ASHI requires the report to state the method used.
Structure, crawlspaces and attics. ASHI 3.2 relieves the inspector of "engineering or architectural services or analysis," of offering "opinions about structural system adequacy," of entering crawlspaces with less than 24 inches of clearance or access openings smaller than 16 by 24 inches, and of traversing "attic load-bearing components concealed by insulation or other materials." So no inspector under either standard may tell you a foundation is adequate — which resolves most "the inspector said the foundation was fine" arguments in the seller's favor — and a great deal of older housing stock fails both crawlspace thresholds, so the sub-floor framing, plumbing and moisture condition of many houses are never seen by anyone.
Plumbing and electrical. InterNACHI excludes wells, pumps and tanks, softeners, and wastewater and septic systems, and does not require determining "the water quality, potability or reliability of the water supply" or testing "for gas or fuel leaks." The inspector need not "insert any tool, probe or device into the main panelboard, sub-panels, distribution panelboards, or electrical fixtures."
Heating and cooling. InterNACHI's heating exclusions cover "the interior of flues or chimneys, fire chambers, heat exchangers, combustion air systems, fresh-air intakes, makeup air, humidifiers, dehumidifiers, electronic air filters, geothermal systems, or solar heating systems." The heat exchanger is the single most expensive concealed component in a furnace and it is explicitly outside the standard. Cooling equipment need not be operated "if the exterior temperature is below 65° Fahrenheit," so a winter inspection in a cold climate routinely leaves the air conditioner untested — compliantly.
Fireplaces and chimneys. ASHI 12.2 excludes "interiors of vent systems, flues, and chimneys not readily accessible," fire screens and doors, seals and gaskets, mantles and surrounds, and combustion air components, and the inspector need not "determine draft characteristics." InterNACHI likewise excludes the flue and vent interior and does not require a Phase I fireplace and chimney inspection. This is why the chimney is the most under-inspected assembly in a house: the component that actually fails is the flue liner, and the flue liner is what both standards leave out.
The single sentence every buyer should read twice
Read InterNACHI 2.2 Part I item 8 alongside ASHI 13.2.F.8: neither standard requires the inspector to determine code compliance. A home inspection is not a code inspection and a home inspector is not a code official. "The inspector didn't tell me it wasn't to code" is the most common consumer complaint about home inspections, and under both standards he was never required to.
The shape of that exclusion is worth understanding. A house built lawfully under an older code is not defective because a current code would require something different, and a report flagging every such difference would be unusable as a negotiating document. Unpermitted work is excluded from another direction: neither standard requires researching property history or determining construction age, so the most a report typically says is that a room "appears to have been added." Its consequences arrive from three other parties — an appraiser who declines to count the square footage, a municipality requiring retroactive permitting, and an insurer excluding the unpermitted portion.
The same logic governs insurability, which InterNACHI 2.1 excludes outright — yet insurability is one of the most common late-stage deal killers, because a carrier reads a report describing certain panel equipment, aluminum branch-circuit wiring, knob-and-tube or polybutylene piping and declines to bind. The inspection surfaces the fact; it does not evaluate the consequence, and the consequence often arrives after the window has closed.
The specialty inspections a buyer must order separately
Each row pairs a specialty inspection with the standard-of-practice text that puts it outside the general inspection, and with the condition that makes it warranted. The general inspector's job is not to perform these — it is to flag the trigger.
| Specialty inspection | What excludes it | When it is warranted |
|---|---|---|
| Sewer scope | ASHI 13.2.E.1, "underground items and storage tanks"; InterNACHI Part III | Houses older than roughly 40 years, mature trees over the lateral, clay or Orangeburg pipe, a history of backups, or slow drains |
| Radon test | InterNACHI 2.2 Part I, "airborne hazards, including radon"; ASHI 13.2.F.12 | EPA and the Surgeon General recommend testing all houses — so every transaction, not only high-radon zones |
| Mold / indoor air quality | InterNACHI 2.2 Part I, "mold, mildew or fungus"; ASHI 13.2.F.11, which names molds | Visible growth, musty odor, elevated moisture readings, prior flooding, a finished basement, or an occupant with a respiratory diagnosis |
| Wood-destroying insect report (NPMA-33) | ASHI 13.2.F.11, "hazardous plants, animals, molds, or life forms"; InterNACHI 2.2 Part I, pests | Required by the lender on most VA loans and many FHA loans in termite-prone areas; warranted with termite pressure, prior treatment, or wood-to-soil contact |
| Structural engineer | ASHI 3.2 and 13.2.B.2, "architectural, engineering, contracting, or surveying services" | Foundation movement, stair-step cracking, out-of-plumb walls, sloping floors, prior underpinning, or expansive soils |
| Chimney evaluation | ASHI 12.2.A.1, "interiors of vent systems, flues, and chimneys not readily accessible" | Any solid-fuel appliance, any chimney with a known fire, any change of fuel type or appliance, and — as the industry treats it — property transfer |
| Pool and spa | Not in either standard's required systems list; ASHI 13.2.E.5 excludes detached structures other than garages | Any in-ground or above-ground pool and any spa; bonding and grounding of pool equipment is a life-safety item |
| Well: yield and potability | InterNACHI plumbing exclusions — "well pumps or tanks," "water quality, potability or reliability of the water supply" | Every private-well property. Flow and yield is one test, water quality another; buying one does not get you the other |
| Septic evaluation | InterNACHI plumbing exclusions, "wastewater treatment systems," "septic systems" | Every septic property. EPA's baseline is that the average household septic system be inspected at least every three years |
| Asbestos survey | InterNACHI 2.2 Part I, "environmental hazards, including lead paint, asbestos" | Pre-1980 construction with duct wrap, pipe insulation, 9x9 floor tile, textured ceilings or cement-asbestos siding — above all before any renovation |
| Lead-based paint risk assessment | InterNACHI 2.2 Part I, environmental hazards | Pre-1978 housing. Federal law gives the purchaser a 10-day period, unless the parties agree in writing otherwise, to conduct a risk assessment or inspection — a statutory window separate from the contract's |
| Thermal imaging | Not required by either standard; an additional service permitted under ASHI 2.3 | Suspected concealed moisture, missing insulation, overheating connections, or radiant-floor tracing. A temperature-differential tool, not an X-ray |
| Geotechnical / soils | ASHI 13.2.F.16, "evaluate soil conditions for geotechnical or hydrologic purposes" | Expansive clay, fill, hillside lots, sinkhole geology, or a structural engineer's recommendation |
| Underground oil tank sweep | ASHI 13.2.E.1, "underground items and storage tanks" | Older houses in regions where oil heat was common. An abandoned or leaking tank is a remediation liability that runs with the land |
Every specialty runs on its own clock
The structural point buyers miss is not that specialty inspections cost extra. It is that each one has its own calendar and the contingency period has only one.
A structural engineer, septic contractor, well tester or chimney professional may have no opening inside a seven-day option period. A radon test needs a monitor deployed at least forty-eight hours under closed-house conditions, and a failed test — closed-house conditions broken by an open window — restarts that clock entirely. A sewer scope requires an accessible cleanout; if the house has none, it may not happen that day at all.
That scheduling reality, rather than cost, is the main reason buyers skip specialty inspections. It also dictates sequence: whatever the property's age and systems already predict should be booked concurrently with the general inspection, not after the report recommends it. Waiting for the recommendation costs days the contingency does not give back.
This is where the exclusions stop being academic. A remedy that exists in the contract but cannot be exercised before the deadline is not a remedy. A buyer who is right but late ends up where a buyer who is wrong ends up.
Who is allowed to call himself a home inspector
There is one more thing a home inspection does not automatically come with: the credential behind it. Licensing is a state matter and it is not universal. InterNACHI's own licensing hub states plainly that among states and provinces, "some regulate home inspectors by issuing licenses and some do not."
Published counts should be handled carefully. One 2026 industry survey identifies sixteen jurisdictions with no state-level licensing requirement, leaving roughly thirty-four states plus the District of Columbia that license or register — but that list conflicts with primary law in at least one case: Massachusetts appears on it, yet Massachusetts has a Board of Registration of Home Inspectors and a codified chapter of limitations and exclusions at 266 CMR 6.05. The structural fact is reliable; the exact count is not. Check your own state board before relying on any tally.
The consequence in a state that does not license is blunt: there is no state credential to check, no state board to complain to, and nothing stopping any person from printing a business card that says "home inspector." That is a statement about recourse rather than competence. In a licensed state a complaint has somewhere to go; in an unlicensed state it has a courtroom or nowhere.
Three filters remain, and they are contractual rather than statutory. Membership and certification in ASHI or InterNACHI impose the Standards of Practice and a code of ethics by association rule rather than by statute — weaker than law and much better than nothing, because it gives the report a defined scope you can hold it to. Errors-and-omissions insurance is the practical measure of whether a claim against the inspector could ever be paid. And a full sample report on a comparable house shows how that inspector distinguishes a safety hazard from a maintenance note. HUD's consumer form makes the point obliquely by telling buyers to ask the prospective inspector for their Standards of Practice — the right question in every state, and the only meaningful one where nobody is licensed.
Frequently Asked Questions
Does a home inspection cover mold?
No. Both standards exclude it: InterNACHI states the inspector is not required to determine "the presence of mold, mildew or fungus," and the current ASHI edition names molds among the life forms the inspector need not identify. Identification requires sampling and a laboratory — a different service by a different professional.
What a general inspector can do is report the observable predicates — water staining, elevated moisture readings, musty conditions, a failed shower pan — and recommend evaluation. Remember that mold is a symptom: the negotiation that follows is usually about the water intrusion causing it.
Does the home inspector check the sewer line?
No. Underground items are excluded from both standards — ASHI 13.2.E.1 covers "underground items and storage tanks" and InterNACHI's residual exclusions cover underground items including irrigation systems and storage tanks. The inspector will run the fixtures and can report slow drainage, but he is not seeing the lateral.
A sewer scope is a separate service running a camera down the lateral from a cleanout. It is warranted on any house older than roughly forty years, any lot with mature trees over the line, clay or Orangeburg pipe, a history of backups, and any time the general report notes slow drains. The economics are lopsided: hundreds for the scope against thousands to tens of thousands for a replacement.
Will the inspector walk on the roof?
Not necessarily, and he is not required to. InterNACHI expressly does not require the inspector to "walk on any roof surface" or to remove "snow, ice, debris or other conditions that prohibit the observation of the roof surfaces," and both standards exclude performing any unsafe act. A roof examined from a ladder at the eave, from the ground, or through binoculars is a compliant inspection.
Does a home inspector check for code violations?
No. ASHI 13.2.F.8 excludes assessing code compliance and InterNACHI excludes determining "compliance with codes or regulations." A home inspection is not a code inspection and a home inspector is not a code official.
A related exclusion is worth knowing. Neither standard requires researching property history or determining construction age, so unpermitted work usually appears only as an observation that something "appears to have been added." Its consequences come from the appraiser, the municipality and the insurer — not from the inspection report.
Why was the air conditioner not tested?
Almost certainly the outdoor temperature. InterNACHI does not require the inspector to operate cooling equipment "if the exterior temperature is below 65° Fahrenheit, or when other circumstances are not conducive to safe operation or may damage the equipment." Running a compressor in cold weather can damage it, so the restriction protects the equipment as much as the inspector.
A winter purchase in a cold climate therefore often comes with an entirely untested cooling system, and the report is compliant in saying so. Inside the window your options are a separate evaluation by an HVAC contractor who can assess the equipment without operating it, or a negotiated position reflecting an unknown of that size.
Does the inspector check the furnace heat exchanger?
No. InterNACHI's heating exclusions name heat exchangers directly, alongside the interior of flues and chimneys, fire chambers, combustion air systems, humidifiers, electronic air filters, geothermal and solar heating systems. The heat exchanger is concealed, and both standards are visual and non-invasive by definition.
That matters more than most exclusions, because the heat exchanger is the most expensive concealed component in a furnace and a cracked one is a combustion-safety problem rather than a comfort problem. An inspector may report visible indicators — flame disturbance, scorching, corrosion at the cabinet — and refer the unit for a combustion analysis. Treat that referral as urgent.
Are home inspectors licensed in every state?
No. Licensing is a state matter and a substantial minority of states do not license or register home inspectors at all. Published lists of which states do and do not are inconsistent with each other and occasionally with primary law, so check your own state board rather than a national tally.
In an unlicensed state there is no credential to verify, no board to complain to, and no legal barrier to anyone using the title. The available substitutes are association membership and certification, which impose the Standards of Practice contractually, errors-and-omissions coverage, and a full sample report you have actually read.