Home inspection standards of practice: ASHI, InterNACHI, and the states

The ASHI and InterNACHI standards have the same shape. Each one covers homes with four or fewer units. Each one has a section for every major system: roof, exterior, structure, heating, cooling, plumbing, electrical, fireplaces, insulation and ventilation, and the interior. For each system it says what the inspector shall inspect and what they shall describe in writing.

Both say the inspection is not technically exhaustive. Neither requires the inspector to judge code compliance, the cause of a condition, repair costs, market value, or whether to buy. Mold, pests, and other environmental hazards are left out of both. For what an inspector can still report about termites, and the license a termite report takes, see can a home inspector do termite inspections.

This table compares the ASHI Standard of Practice in force, effective March 1, 2014, with the InterNACHI Standards of Practice, last revised October 2022. Each row is quoted from both texts:

The report rules differ too. ASHI's report lists systems that are not working properly, significantly deficient, unsafe, or near the end of their service lives, with recommendations. It also names anything present but not inspected, and why. InterNACHI's report identifies the defects the inspector observed and judged material. For how a new inspector uses the standard as a checklist on site, see what to expect on a first paid inspection.

ASHI members approved a revised Standard in a vote that closed January 8, 2026. ASHI's page on the changes now lists an implementation date of January 1, 2027. Its main Standard of Practice page still says more on the date will follow, and the ASHI president's letter in the October 2026 ASHI Reporter gave January 31, 2027 as the target. Until it takes effect, the 2014 Standard is the one in force.

The approved text makes these changes, among others:

• Decks and balconies get their own section, and so does the garage and carport.
• Heating and air conditioning merge into one HVAC section.
• Insulation and ventilation split into two sections.
• The crawlspace and attic entry limit rises to 30 inches of clearance and an 18 by 24 inch opening.
• It says walking on roofs is not required.
• Removing the covers of service panels and subpanels is named as the one exception to its no-dismantling rule.
• Where the Standard and the law conflict, the law takes precedence.

In a state with its own SOP, the state's rule is the one a licensed inspector works under. These 23 states set their own in statute or rule, as of October 14, 2026: Alabama, Connecticut, Florida, Illinois, Indiana, Louisiana, Maryland, Massachusetts, Nevada, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Rhode Island, Tennessee, Texas, Vermont, Virginia, Washington, Wisconsin.

Five more lean on an association's text:

• Arizona. Its rule adopts the standards of the Arizona Chapter of ASHI, as adopted on October 27, 2023.
• Arkansas and Mississippi adopt the ASHI Standards of Practice.
• Kentucky. Its statute requires the ASHI or InterNACHI standard, or one the board approves as equal.
• South Carolina. The licensing agency's FAQ says the state uses the ASHI Standards of Practice. No rule that says so was found.

Some states with no license still point to association standards. Pennsylvania's law tells a court to consider national associations' standards of practice. Iowa's standard of care rests on a national association's standards without naming one. California sets a standard of care with no SOP of its own.

Alaska's statute refers to standards the state adopts, but its rules contain none. Eight other licensing states were not checked for a standard of their own: Delaware, Montana, Nebraska, New Hampshire, North Dakota, South Dakota, Utah, and West Virginia. For each state's license rules, see home inspector license requirements by state.

The National Home Inspector Exam (NHIE) is not written to any one standard. Its publisher, EBPHI, says many associations have their own, and it keeps the test apart from all of them. For more information, see what is EBPHI? For how the two associations compare on dues, exams, and titles, see ASHI vs. InterNACHI.