What a Home Inspection Does Not Cover

Both InterNACHI and ASHI describe the inspection as covering readily accessible, visually observable, installed systems, and both state that an inspection is not technically exhaustive.

That is not a disclaimer bolted on at the end. It is the definition of the service, and everything below follows from it.

Source: InterNACHI Home Inspection Standards of Practice; ASHI Standard of Practice.

ASHI excludes wells, pumps, pressure tanks, storage tanks and filters. InterNACHI excludes well pumps and tanks and water storage tanks. So on a property with its own water, the equipment that supplies the entire house is outside the inspection that was carried out on it.

The inspector will describe whether the supply is public or private — InterNACHI requires that — but describing is not inspecting.

Both standards exclude septic and other sewage disposal or wastewater treatment systems. The inspector checks that fixtures drain; where the water goes after it leaves the building is not part of the job.

That gap is why a sewer scope is ordered separately, and it is the single most expensive thing a buyer can be unaware of.

InterNACHI states the inspector is not required to determine water flow, pressure, quality or potability. ASHI likewise cannot determine water quality or system adequacy. Water conditioning systems are excluded outright by ASHI.

So a report can be entirely clean on a house whose water is hard, discolored or arriving at a pressure nobody would live with. None of those is a defect the inspection was looking for.

Visual means visual. Pipe inside a wall, under a slab or below grade is not observed, and neither standard asks the inspector to open a sealed access panel to reach it.

InterNACHI goes further and names polybutylene piping in its list of exclusions specifically. On a house of the right age that is a material question, and it is one the inspection is not obliged to answer.

Source: InterNACHI Home Inspection Standards of Practice.

Clothes washer connections (ASHI). Floor drains (InterNACHI). Lawn irrigation (ASHI). Fire suppression and sprinkler systems (both). Testing for gas or fuel leaks (both). Testing a shower pan or tub for leakage (InterNACHI). Anti-siphon devices and backflow preventers.

None of these means an inspector is cutting corners. They are the agreed boundary of the service, published by the bodies that set it.

Read the exclusions in your own report before you read the findings. The findings tell you what was looked at; the exclusions tell you what you still do not know. Deciding what to chase is a different job from reading the report.