A home inspector performs a visual, non-invasive walkthrough of a property’s major systems and visible structure, and what home inspectors look for is defects, safety hazards, and signs of wear in the roof, exterior, foundation, electrical, plumbing, heating and cooling, interior surfaces, insulation, ventilation, and built-in appliances. The job is to document the condition of what can be seen and reached, test systems with their normal controls, and flag anything that needs a specialist. Most inspections take two to four hours and end with a written report the buyer uses to decide what to do next.
The Scope: Visible, Accessible, Non-Invasive
Under the ASHI Standard of Practice, a home inspection is not a technically exhaustive examination. Inspectors evaluate the visible and accessible portions of the structure, exterior, roof, electrical system, plumbing, heating and cooling equipment, interior surfaces, insulation, ventilation, and permanently installed appliances, using normal operating controls to test them.1American Society of Home Inspectors (ASHI). Standard of Practice
Several categories are specifically outside the scope. Concealed conditions behind walls, under floors, or beneath soil are excluded. Latent defects that aren’t visible during the walkthrough fall outside the scope. Cosmetic issues that don’t affect function are also excluded.1American Society of Home Inspectors (ASHI). Standard of Practice An inspector won’t determine code compliance, calculate structural adequacy, or test for radon, mold, or lead paint. They aren’t required to assess the strength or efficiency of any system either.2American Society of Home Inspectors (ASHI). The Standard of Practice for Home Inspections The furnace getting warm is a pass; whether the ductwork is sized correctly isn’t the inspector’s call.
Foundation, Grading, and Exterior
The inspector examines the foundation for visible cracks, settling, and water intrusion. They probe structural components where deterioration is visible or suspected, but they won’t offer an opinion on whether the foundation is structurally adequate.2American Society of Home Inspectors (ASHI). The Standard of Practice for Home Inspections Cracks get documented, displacement gets measured, and anything serious gets referred to a structural engineer.
Water management ties the exterior review together. The inspector checks that the ground slopes away from the foundation at a minimum of half an inch per foot for at least ten feet.3U.S. Department of Energy. Site is Excavated: Final Grade is Sloped Away from Home Poor grading is one of the most common findings and one of the cheapest to fix, but ignoring it leads to basement flooding and foundation damage. Gutters and downspouts are checked for proper attachment and to confirm they discharge water well away from the base of the home.
Siding and masonry get checked for damage that could let moisture or pests into the wall cavity. Windows and doors are tested for proper sealing and smooth operation. On the roof, shingles or other coverings are evaluated for wear, missing sections, and damaged flashing around chimneys and vent pipes.
Retaining walls on the property also come under scrutiny. The inspector looks for rotation or bulging beyond about one inch in eight feet, cracks wider than a quarter inch, blocked drainage openings (weep holes), and erosion under the wall’s base. Any of these can signal a wall that’s failing under soil pressure.4American Society of Home Inspectors, Inc. The Word: Retaining Walls
Electrical System
The inspector opens the main service panel and examines the breakers, wiring connections, and grounding. They watch for double-tapped breakers, where two wires share a single breaker terminal, which is a common finding and a potential fire hazard. Visible wiring in accessible areas is checked for fraying, improper splices, and amateur modifications.
Ground fault circuit interrupter (GFCI) outlets are tested in kitchens, bathrooms, garages, outdoor receptacles, and laundry rooms. The inspector confirms each one trips and resets. Older homes may lack them entirely, which is a safety upgrade worth budgeting for.
Certain older panels and wiring draw extra attention because they carry documented safety risks and can affect insurability. Federal Pacific Electric (FPE) panels with Stab-Lok breakers, commonly installed between 1950 and 1985, have breakers known to fail to trip during an overload. Zinsco panels, installed starting in the 1940s, develop connection problems because their aluminum components expand and contract at a different rate than the copper or brass they connect to. Either panel type is likely to trigger a recommendation for full replacement. Aluminum branch wiring, common in homes built during the 1960s and 1970s, creates connections significantly more likely to reach fire-hazard conditions than copper. Some insurers refuse to cover homes with these components or require remediation before issuing a policy.
Plumbing
The inspector locates the main water supply line and checks distribution pipes in accessible areas for corrosion, leaks, and material type. Faucets are run to test water pressure and flow, and the inspector looks under sinks and around toilets for active leaks or water damage. The drainage and vent system is evaluated to confirm waste exits the home without backup or sewer gas odor.
The water heater gets particular attention. The inspector notes its age, checks for a properly installed temperature and pressure relief (TPR) valve, and confirms the discharge piping routes safely. A missing or obstructed TPR valve is a direct safety hazard because it prevents pressure from being released if the water overheats.5HUD.gov. NSPIRE Standard – Water Heater V2.1 Tank water heaters have an average service life of roughly 8 to 12 years depending on installation, maintenance, and water chemistry, so age alone can signal replacement budgeting.
Pipe material matters more than most buyers realize. Polybutylene pipes, a gray flexible plastic installed in millions of homes from the late 1970s through the mid-1990s, become brittle and crack from the inside out after prolonged contact with chlorine in municipal water. The deterioration happens internally, so the pipes can look fine from the outside while failing within. A billion-dollar class action settlement in 1995 confirmed the scope of the problem. Inspectors identify polybutylene by its gray color, flexibility, and the “PB2110” stamp, and its presence is worth flagging even though the standard of practice doesn’t require it.
Heating and Cooling
The inspector activates the heating and cooling systems using the thermostat to confirm they respond and produce conditioned air. The furnace or boiler is checked for proper combustion and safe venting of exhaust gases. Ductwork and distribution components are examined for physical damage or disconnections that could waste energy or push combustion gases into living spaces. Filter condition gets noted because a neglected filter strains equipment and shortens its life.
HVAC systems generally last 15 to 25 years depending on equipment type and maintenance. The inspector documents the approximate age of each unit so you can estimate remaining life and plan for replacement, which routinely runs into the thousands.
Weather limits what can safely be tested. Running the air conditioning when outdoor temperatures are below roughly 60 degrees can damage the compressor because refrigerant may condense into liquid and slug the mechanical components. Extremely hot weather can prevent a meaningful heating test. When conditions prevent testing, the report documents the limitation rather than risk equipment damage. This is normal.
Interior and Attic
Inside the home, walls, ceilings, and floors are examined for stains, cracks, and evidence of water damage. Sagging floors or significant wall cracks can point to problems with floor joists or the foundation that warrant further investigation. Cosmetic flaws aren’t the target; visible evidence of structural or moisture trouble is.
The attic reveals a lot about a home’s health. The inspector checks insulation levels, looks for daylight penetrating the roof sheathing, and examines the underside of the roof deck for water stains or wood deterioration. Ventilation is assessed, though the real culprit behind attic mold and moisture damage is usually air leaks from the living space below rather than inadequate ridge or soffit vents. Warm, humid household air that escapes into a cold attic hits cold surfaces and condenses, creating ideal conditions for mold on the roof sheathing. Bathroom exhaust fans that terminate in the attic instead of outside are one of the most common contributors.
Stairs and railings are checked for stability and safe configuration. Fireplaces are inspected for visible damage to the firebox and chimney flue, though a detailed chimney interior review requires a separate specialist.
Built-In Appliances and Safety Devices
The inspector tests permanently installed appliances by running them through their primary function: ovens, ranges, cooktop burners, microwave ovens, dishwashers, and garbage disposals.2American Society of Home Inspectors (ASHI). The Standard of Practice for Home Inspections The testing is functional, not performance-based. The oven heats; its thermostat doesn’t get calibrated. Free-standing appliances like refrigerators and washers and dryers are excluded from the standard inspection.
Smoke detectors and carbon monoxide alarms are checked for presence and basic function. Best practice places them on every level of the home and near each sleeping area. The inspector documents what’s present and what’s missing so you can address gaps before moving in.
The Findings That Carry Real Weight
Not every item in a report matters equally. A dripping faucet is a minor repair. A failing foundation, active roof leak, or outdated electrical panel is a different conversation. Experienced inspectors sort findings by whether a defect poses an unreasonable risk to people, hurts property value, or signals a system nearing the end of its useful life.
The findings most likely to prompt renegotiation or a walk-away include active water intrusion in the basement or crawlspace, a roof needing near-term replacement, Federal Pacific or Zinsco electrical panels, evidence of structural movement, and major plumbing issues like polybutylene supply lines or a sewer lateral in poor condition. Any of these can carry five-figure repair costs, and they often don’t surface until a trained eye goes looking. This is where the inspection earns its fee.
What a Standard Inspection Won’t Touch
Some of the most expensive problems in a home sit outside the general inspector’s scope and need their own specialist. Knowing which to order depends on the property’s age, location, and features.
Radon Testing
Radon is a naturally occurring radioactive gas that seeps into homes through foundation cracks and gaps. It’s the second leading cause of lung cancer in the United States, and you can’t see or smell it. The EPA recommends mitigation for homes with radon levels at or above 4 picocuries per liter (pCi/L) and suggests considering mitigation for levels between 2 and 4 pCi/L because there is no known safe level of exposure.6US EPA. What is EPAs Action Level for Radon and What Does it Mean A professional test places a monitor in the lowest livable area for at least 48 hours.
Lead Paint
For homes built before 1978, federal law requires sellers to disclose any known lead-based paint information and give buyers a 10-day window to have the paint tested by a certified inspector before the contract becomes binding.7US EPA. Real Estate Disclosures about Potential Lead Hazards Homes where all painted surfaces have been tested and certified lead-free are exempt from the disclosure rule.
Sewer Scope
A sewer scope sends a waterproof camera through the underground pipe connecting the home to the municipal sewer line. The live video reveals tree root intrusions, pipe collapses, grease buildup, and cracks that no surface inspection can detect. It’s especially valuable for older homes with clay or cast iron laterals and properties with large trees near the sewer path. A failed lateral can easily reach $10,000 or more to replace.
Wood-Destroying Organisms
Termite and pest inspections are separate from the general inspection and are often required by the buyer’s lender. Inspectors look for mud tubes along the foundation, discarded wings near windows and doors, and wood damage in accessible structural members. In many regions, this inspection is standard even when the lender doesn’t require it.
What to Do With the Report
The report is a negotiating tool, not a pass-or-fail grade. Most purchase agreements include an inspection contingency giving the buyer a set number of days to complete inspections and respond, commonly 7 to 14 days. After reviewing, buyers generally accept the property as-is, ask the seller to make repairs or provide a credit at closing, or terminate the agreement if the findings are severe. The items worth pressing on are the ones that affect safety, structural integrity, or major systems. A report with 30 findings is normal for any home over a few years old; the ones that matter are the ones that cost real money or pose genuine safety risks.