The short answer, before the detail
In every area of a house, a home inspection has two lists: what the inspector shall inspect, and what the inspector is not required to do. Both are published, both are short, and the second is where buyers are surprised — the roof need not be walked, an inaccessible crawlspace need not be entered, the chimney flue is outside the scope entirely, and no standard lets an inspector tell you how many years a component has left.
What follows walks the house in the order you would walk it, giving the required work and the exclusions with section numbers from the InterNACHI Residential Standards of Practice (last revised October 2022), the ASHI Standard of Practice, the Arizona Board of Technical Registration’s adopted standards and the Texas Real Estate Commission’s rules. Where a standard is silent, we say so rather than borrowing a number.
One boundary applies throughout: both national standards cover buildings with four or fewer dwelling units, plus attached and detached garages. A unit in a larger building is a narrower job — what a condominium unit inspection covers belongs with a site that handles associations and common elements.
Exterior, grounds and drainage
ASHI gives the exterior its own section at 4.0 and, in the version carrying approved changes as of 8 January 2026, splits Deck and Balcony into a standalone section 5.0 — worth knowing, because older editions folded decks into the exterior and older checklists still do. The Texas form puts the same ground under Structural Systems: grading and drainage at I.B, porches, balconies, decks and carports at I.K.
The exclusions here are mostly about the land rather than the building. Section 2.2 states the inspector is not required to determine property boundary lines — a home inspection is not a survey and will not tell you where the fence should be. The same section excludes the presence of pests, determining the cause of any condition and predicting future ones, and Arizona’s standards exclude determining “the presence or absence of any suspected environmental hazards.”
Soil behavior is a regional subject rather than a standards subject. In North Texas, the relationship between clay soil, moisture and foundation movement is a local question with local answers, outside what any national standard asks an inspector to determine.
The roof
The most misunderstood area in the house, and the one where the two lists diverge most sharply.
Required. InterNACHI section 3.1 requires the inspector to inspect “the roof-covering materials, gutters, downspouts, vents, flashing, skylights, chimney and other roof penetrations” and “the general structure of the roof from the readily accessible panels, doors or stairs,” and to report an active roof leak as needing correction.
Not required. The same section states the inspector need not “walk on any roof surface.” Nor predict service life, remove snow, ice or debris, perform a water test, or “warrant or certify the roof.” Every one of those is a thing buyers assume they are getting.
So the method is the inspector’s choice — the surface, a ladder at the eaves, the ground, an upper window, a drone — and the standard permits all of them. The method is not a defect in the inspection; failing to tell you which was used is. Massachusetts sharpens this: its definition of readily accessible excludes anything requiring the inspector “to resort to portable ladders,” narrower than the ASHI and Illinois definitions, neither of which mentions ladders.
The attic, insulation and ventilation
Required. InterNACHI section 3.9 requires the inspector to describe “the type of insulation observed” and “the approximate average depth of insulation observed at the unfinished attic floor area or roof structure,” and to report a general absence of insulation or ventilation in unfinished spaces.
Not required. To enter inaccessible attics. To “move, touch or disturb insulation.” To “identify the composition or R-value” of what is there. To determine whether ventilation is adequate.
Read those together and the shape of the finding is clear. You get a description and an approximate depth. You do not get an R-value, and you do not get a verdict on whether the attic is sufficiently insulated or ventilated, because adequacy of any system is excluded outright at 2.2. An attic report is a description, not an assessment — which is the line between a home inspection and an energy audit.
The basement, crawlspace and foundation
Required. InterNACHI section 3.3 requires the inspector to report wood in contact with soil, active water penetration, and indications of foundation movement.
Not required. To enter inaccessible crawlspaces. To move debris. To operate sump pumps. To determine the adequacy of the foundation. To identify joist sizing. To assess the adequacy of the structural system. And, stated in as many words, to “provide any engineering or architectural service.”
That last exclusion is the most consequential sentence in the standard. “Indications of foundation movement” is an observation; “the foundation is adequate” is an engineering opinion, and the inspector is barred from offering it. Arizona’s board builds the same wall from the other side: inspectors need not “calculate the strength, adequacy, or efficiency of any system.” When a report says a structural condition needs further evaluation, that is not a gap in the work — it is the point at which a different license is required.
Inside the rooms: interiors, stairs and fireplaces
ASHI gives interiors their own section at 10.0 and fireplaces and fuel-burning appliances at 13.0. The Texas form distributes the same material across Structural Systems: walls at I.E, ceilings and floors at I.F, doors at I.G, windows at I.H, stairways at I.I, fireplaces and chimneys at I.J. Either way, a room is not a unit of inspection — the components in it are, reported under system headings rather than under “the back bedroom.” That is the biggest mismatch between how a buyer walks a house and how a report is filed.
The fireplace exclusion is the one to know. InterNACHI section 3.8 requires inspection of readily accessible portions of the fireplace and chimney, lintels, damper doors and cleanout doors. It then states the inspector is not required to “inspect the flue or vent system,” to inspect chimney interiors, to determine the need for a chimney sweep, to “perform a smoke test,” or to “perform a National Fire Protection Association (NFPA)-style inspection.” Everything inside the chimney is outside the inspection — so a report silent on the flue is not telling you the flue is sound.
One more exclusion governs every interior surface: both national standards put cosmetic imperfections outside the scope, ASHI by name and InterNACHI as aesthetic concerns. Tennessee is the only jurisdiction reviewed that defines the term, as “superficial blemishes or defects that do not interfere with the functionality of the component or system.”
Kitchens, bathrooms and the plumbing system
Required. InterNACHI section 3.6 requires the inspector to inspect the main water shut-off valve, the main fuel shut-off valve, water heating equipment, the interior water supply by running water, toilets by flushing them, sinks, tubs and showers by draining them, and the drain, waste and vent system.
Not required. To “measure the capacity, temperature, age, life expectancy or adequacy” of the water heater. To determine “exact flow rate, volume, pressure, temperature.” To determine water potability. To “operate any valve.” To test shower pans for leakage. To inspect wastewater systems.
Four of those are worth sitting with. The water heater will be looked at and not aged, rated or sized. Pressure will be observed in operation and not measured. The water will not be tested — HUD’s buyer notice lists water quality among the conditions needing separate specialist testing. And the septic system is not part of a home inspection at all.
Electrical, heating and cooling
Electrical, required. InterNACHI section 3.7 requires inspection of the service drop, service-entrance conductors, main disconnect, panelboards, over-current protection devices, grounding and bonding, representative switches, fixtures and receptacles, AFCI and GFCI devices, and smoke and carbon monoxide detectors. Two conditions must be reported rather than merely noticed: the absence of detectors, and the presence of solid aluminum branch wiring.
Electrical, not required. To “insert any tool, probe or device into” the panel. To operate over-current protection devices. To “measure or determine the amperage or voltage.” To “verify the service ground.” To inspect low-voltage, security or alarm systems.
That list is why an electrical finding so often arrives attached to a recommendation for an electrician. The inspector may open the panel and look; measuring is somebody else’s job by rule, not by preference.
Heating and cooling. ASHI covers HVAC at 9.0 and venting systems at 12.0; the Texas form splits heating equipment, cooling equipment, and duct systems, chases and vents. What governs here is less the required list than two exclusions. Arizona’s standards state inspectors need not “operate any system or component which is shut down,” so a unit that could not safely be run is a unit nobody confirmed. And life expectancy is excluded by ASHI, InterNACHI, Texas and Arizona alike — an inspector who tells you how long the furnace has left is working outside the standard.
The garage, and the pattern underneath all of it
ASHI gives the garage and carport their own section at 14.0, and both national standards include attached and detached garages; the Texas form handles carports at I.K. The garage is where exclusions stack up fastest, because it is where stored property lives: anything requiring the inspector to move personal property falls outside readily accessible under the ASHI, Illinois and Massachusetts definitions alike.
Set the eight areas side by side and the same shape appears in each.
| Area | Required, in short | Excluded, in short |
|---|---|---|
| Exterior and grounds | Exterior surfaces, decks and balconies, grading and drainage | Boundary lines, pests, environmental hazards, cause of any condition |
| Roof | Coverings, flashing, penetrations, skylights, gutters; report active leaks | Walking the roof, water testing, service life, certifying or warranting it |
| Attic | Insulation type and approximate depth; absence of insulation or ventilation | Entering inaccessible attics, disturbing insulation, R-value, adequacy of ventilation |
| Basement and crawlspace | Wood in contact with soil, active water penetration, indications of movement | Entering inaccessible spaces, foundation adequacy, joist sizing, engineering service |
| Interiors and stairs | Walls, ceilings, floors, doors, windows, stairways | Cosmetic imperfections and aesthetic concerns |
| Fireplace | Readily accessible fireplace and chimney, lintels, dampers, cleanouts | The flue and vent system, chimney interiors, smoke tests, NFPA-style inspection |
| Plumbing | Shut-offs, water heating equipment, fixtures run and drained, drain-waste-vent | Water heater age and capacity, pressure and flow, potability, shower pans, septic |
| Electrical | Service, panels, over-current devices, grounding, representative devices, alarms | Probing the panel, measuring amperage or voltage, verifying ground, low-voltage systems |
Three rules run underneath every row. The inspection is visual and “not technically exhaustive” — ASHI’s limitations, InterNACHI’s 2.1 and Arizona’s 3.1A say so in nearly identical words. It will not identify concealed or latent conditions; Texas’s rules put it as “anything buried, hidden, latent, or concealed.” And none permits a determination about adequacy, remaining life, cause, future conditions, code compliance or cost of repair. Those six absences are the actual scope of a home inspection. Next: what they mean for your decision, or the same material as questions to ask on the day.
Frequently Asked Questions
Does the home inspector have to go on the roof?
No. InterNACHI's standards state the inspector is not required to “walk on any roof surface.” Inspecting from a ladder at the eaves, from the ground, from an upper window or by drone all satisfy the standard. What you are entitled to know is which method was used, because that determines how much of the covering was actually seen. Massachusetts goes further and excludes portable ladders from its definition of readily accessible altogether.
Does the inspector enter the attic and the crawlspace?
Only where they are accessible. The standards do not require an inspector to enter inaccessible attics or inaccessible crawlspaces, to move debris, or to move stored property. An inspection conducted from the access opening is a compliant inspection and a much less informative one, so the report should say which it was — Illinois, Massachusetts and North Carolina all require the reasons for a non-inspection to be recorded.
Is the chimney flue inspected?
No. InterNACHI's fireplace section states the inspector is not required to inspect the flue or vent system, to inspect chimney interiors, to determine the need for a chimney sweep, to perform a smoke test, or to perform an NFPA-style inspection. A general inspection that says nothing about the flue is not telling you the flue is sound; it is telling you the flue was never in scope.
Is the septic system part of a home inspection?
No. Wastewater systems are expressly excluded from the plumbing section of the InterNACHI standard, and HUD's buyer notice treats conditions of that kind as needing separate specialist attention. A septic evaluation is a separate service with its own scope and its own report, and ordering one is a decision to make before the inspection, not after.
Will the inspector tell me how old the water heater is?
Not under the standard. InterNACHI's plumbing section excludes measuring “the capacity, temperature, age, life expectancy or adequacy” of the water heater. Many inspectors will note a data plate as a courtesy, which is useful and is not a required finding. Service life is excluded across the board — by ASHI, by InterNACHI, by Texas rule and by Arizona's adopted standards.
Why does the inspector open the electrical panel but not test anything?
Because the standard draws the line there. The inspector must inspect the panelboards, over-current protection devices, grounding and bonding and representative devices, and must report the absence of smoke and carbon monoxide detectors and the presence of solid aluminum branch wiring. The same section forbids inserting any tool or probe into the panel, operating over-current protection devices, measuring amperage or voltage, and verifying the service ground.
Does the inspection cover the yard, the fence line or the retaining wall?
Partly. Exterior surfaces, grading and drainage are within scope, and decks and balconies have their own ASHI section. But property boundary lines are excluded by name, so nothing in the report establishes where a fence should sit, and the standards exclude determining the cause of any condition or predicting future ones. For a grounds question that drives the purchase, the inspection is a starting point rather than an answer.
Does a condo unit get inspected the same way?
No. Both national standards are written for buildings with four or fewer dwelling units plus their garages and carports, so a unit inside a larger building is a narrower job with a boundary at the unit line. The association's reserves, common elements and master insurance are a different subject with a different document set, and belong with a site that covers condominium associations rather than here.