A home inspection consists of a visual, non-invasive examination of a house’s major systems and structural components, carried out by a licensed inspector who then issues a written report describing what works, what doesn’t, and what needs attention. The inspector follows a defined standard of practice (most commonly those published by the American Society of Home Inspectors or the International Association of Certified Home Inspectors) and typically spends two to four hours on-site depending on the size of the property. A standard inspection costs between $200 and $500 and documents the home’s condition on the day of the visit.
What the inspection covers falls into predictable categories. What it leaves out matters just as much, because a clean report doesn’t mean a problem-free house. Both halves are below.
Inspection vs. Appraisal
These two steps get confused constantly. An appraisal estimates the home’s market value and is almost always ordered by the lender before a mortgage is approved. A home inspection evaluates whether the home’s systems and structure are safe and functional. The appraiser answers “what is this house worth?” The inspector answers “what’s wrong with it?” One does not substitute for the other. An appraiser won’t climb into the attic or pull the cover off the electrical panel; an inspector won’t compare neighborhood comps to price the property.
Structure, Roof, and Exterior
The inspector starts outside with the home’s physical shell. The foundation is checked for visible cracking, displacement, and signs of water intrusion. Exterior walls, siding, trim, and flashing are examined for damage. Windows and doors are opened and closed to confirm they operate smoothly without binding or broken hardware. The roof covering is assessed visually for wear, missing material, and the condition of flashings around chimneys, skylights, and other penetrations.1American Society of Home Inspectors, Inc. Standard of Practice
Drainage gets real attention. The inspector checks whether the soil around the foundation slopes away from the house so surface water doesn’t pool against the walls, and whether gutters and downspouts are placed and sized to carry water clear of the structure. Attached decks, balconies, and porches are inspected for secure connections to the house and the condition of their railings and walking surfaces. A deck pulling away from the house or a porch with rotted framing gets flagged as a significant defect.
Plumbing
Inside, the inspector traces visible water supply and drain lines looking for leaks, corrosion, or improper materials. Faucets are turned on throughout the house to check functional water pressure and watch for slow drains or backups. Hidden pipes behind finished walls aren’t pressure-tested, but anything visible and accessible is examined.
Water heaters get specific scrutiny. The inspector confirms that a temperature and pressure relief (TPR) valve is present and unobstructed, and that the discharge piping is routed correctly (not capped, not sloping upward, and made of suitable material). On fuel-fired units, the flue is checked for proper alignment and connection so exhaust vents outside instead of leaking into living spaces.2Department of Housing and Urban Development. NSPIRE Standard – Water Heater V2.1
Electrical
The electrical review begins at the main service panel. The inspector removes the panel cover to examine breakers, wiring connections, and overall condition. Signs of overheating, double-tapped breakers (two wires on a breaker not rated for both), and improper wire gauges are documented. The panel’s amperage rating is noted, though a true load calculation for your intended use is an electrician’s job.
Throughout the house, a representative sample of outlets and light fixtures is tested to confirm power, correct polarity, and intact grounding. Outlets near water get extra attention. Ground fault circuit interrupter (GFCI) protection is expected in bathrooms, kitchens, garages, outdoor locations, and anywhere moisture creates a shock hazard. The inspector presses the test button on each GFCI to confirm it trips and cuts power. A GFCI that won’t trip is a safety defect.
Heating and Cooling
The inspector operates the heating system from the thermostat to confirm it responds and actually produces heat. Visible ductwork is checked for disconnected sections, major gaps, or damage that would starve certain rooms of airflow. Filters are inspected for condition and fit.
Air conditioning gets tested when outdoor temperatures cooperate. Most inspectors won’t run a compressor below about 60°F because doing so can damage the equipment. When conditions allow, the system is started and the temperature difference between supply and return vents is measured to gauge cooling performance. The condensate drain line is checked because a clog in summer sends water into ceilings and walls. Supply vents around the house are examined for obstructions and airflow.
Interior, Appliances, and Attic
Inside the living spaces, walls, ceilings, and floors are examined for cracks, water stains, and structural damage. Stairs are tested for stability, and handrails are checked for secure mounting and safe height. Built-in appliances that convey with the home (dishwasher, oven, range) are run through a basic cycle to verify they power on and function.
In the attic, the inspector notes insulation depth and type and compares what’s there against recommended R-values for the region. The Department of Energy recommends R-49 to R-60 for attic floors in most U.S. climate zones, with warmer southern regions needing a minimum of R-30.3Department of Energy. Insulation Visible ventilation components such as ridge vents and soffit vents are checked to confirm air can circulate through the attic. Poor attic ventilation accelerates roof wear and can trap moisture that leads to mold.
What a Standard Inspection Does Not Cover
This is where misunderstanding does the most damage. A home inspection is not an exhaustive engineering analysis, and the professional standards explicitly limit the scope. Knowing the boundaries keeps you from reading a clean report as proof the house has no hidden problems.
Concealed and Inaccessible Areas
Inspectors evaluate only what they can see and safely reach. They won’t move furniture, lift carpeting, remove wall panels, or cut into drywall. If a finished basement wall conceals a foundation crack, or stored boxes block the electrical panel, those items go unexamined. The report typically notes “not inspected” for anything the inspector couldn’t access. Conditions hidden behind surfaces, underground, or in locked areas are outside the scope.1American Society of Home Inspectors, Inc. Standard of Practice
Environmental Hazards
Standard inspections do not test for lead paint, asbestos, mold, radon, or other environmental contaminants. The inspector is not required to evaluate the presence of toxins, carcinogens, or radioactive substances in building materials, soil, water, or air. Underground storage tanks, active or abandoned, are also excluded.1American Society of Home Inspectors, Inc. Standard of Practice Any concern on this list requires a specialist and a separate test.
Code Compliance
Home inspectors are not required to determine whether any system or component complies with current building codes. Both ASHI and InterNACHI say so plainly in their standards of practice. The inspector evaluates whether something is functioning, safe, and in reasonable condition. A wiring method that was acceptable when the house was built but wouldn’t pass today’s code isn’t necessarily flagged unless it creates an actual safety concern. A code compliance review is the job of a municipal building inspector.
Cosmetic Issues and Remaining Lifespan
Scuffed paint, wallpaper condition, minor surface scratches, and cosmetic blemishes are excluded. The inspector also won’t predict how many years the roof, furnace, or water heater has left. The report captures current condition, not future performance. You may see a note that a system “appears near the end of its service life,” but a firm expiration date is beyond the scope.1American Society of Home Inspectors, Inc. Standard of Practice
Add-On Inspections Worth Considering
Because the standard inspection leaves out several significant hazards, buyers in certain situations should pay for targeted add-ons. These are performed by specialists or by a general inspector with additional certifications, and they’re usually scheduled alongside the main inspection.
Radon Testing
Radon is an odorless, invisible radioactive gas that seeps into homes from the ground and is the second leading cause of lung cancer in the United States. A standard inspection won’t detect it. Professional radon testing uses either passive devices (such as charcoal canisters) or active continuous monitors, and the test must run for a minimum of 48 hours. The EPA recommends fixing the home if radon levels reach 4 picocuries per liter (pCi/L) or higher, and suggests considering mitigation at levels between 2 and 4 pCi/L.4Environmental Protection Agency (EPA). What is EPAs Action Level for Radon and What Does it Mean Radon testing as an add-on typically runs $90 to $250.
Sewer Scope
A sewer scope sends a video camera through the main drain line from the house to the municipal connection or septic tank. The inspector records the entire run and reports root intrusion, cracks, pipe offsets greater than a quarter inch, crushed or collapsed sections, and blockages.5InterNACHI. InterNACHI Sewer Scope Inspection Standards of Practice Sewer line repairs can easily cost $5,000 to $15,000, so the $150 to $500 a scope costs is cheap insurance, especially on older homes with clay or cast iron pipes. You get the video recording along with the written report.
Wood-Destroying Organism Inspection
A wood-destroying organism (WDO) inspection focuses on evidence of termites, powder post beetles, carpenter ants, and similar pests. Many lenders require a WDO report before funding a mortgage, particularly for VA and FHA loans. The specialist documents visible evidence of current or past activity and notes conditions that invite infestations, such as wood in direct contact with soil or excessive moisture in crawl spaces. A WDO inspection confirms whether evidence exists and where; it doesn’t quantify structural damage. Expect to pay $75 to $300 for a standalone WDO inspection.
Other Common Add-Ons
Depending on the property, you might also want a pool and spa inspection (pumps, filters, heaters, barriers, safety equipment), a septic system evaluation, well water testing, or a mold assessment. Each one adds cost but addresses a hazard the standard inspection leaves untouched. Your inspector or real estate agent can help you decide which make sense for the specific property.
The Report You Receive
After the walkthrough, the inspector compiles a written report documenting every system and component examined. Most inspectors deliver it digitally within 24 to 48 hours. The report includes photographs of specific concerns alongside written descriptions explaining the nature and significance of each finding. Items are categorized by system (roof, plumbing, electrical) and flagged by severity so you can quickly tell a safety hazard from a minor maintenance item.1American Society of Home Inspectors, Inc. Standard of Practice
The report goes to you and, with your permission, to your real estate agent. It represents the home’s condition on the day of the inspection, not a warranty or a prediction. Most inspection agreements include a limitation of liability clause that caps potential damages at the fee paid for the service, so the document is an informational tool rather than an insurance policy. Used alongside the right add-ons, it tells you what you’re buying.