A home inspector looks at the parts of a house you can see without opening walls: the structure and foundation, the roof and exterior, the plumbing and electrical systems, the heating and cooling equipment, the interior finishes, the attic, and the built-in kitchen appliances. What do home inspectors look at that most buyers don’t expect, and what do they leave alone? The scope is defined by a published standard, and understanding where it stops matters as much as knowing where it reaches. The American Society of Home Inspectors (ASHI) Standard of Practice requires an inspector to evaluate readily accessible, visually observable systems and components, then deliver a written report flagging anything that is not functioning properly, significantly deficient, unsafe, or near the end of its useful life.1American Society of Home Inspectors, Inc. Standard of Practice “Readily accessible” is the whole game. No drywall gets cut. No carpet gets pulled. No foundation gets excavated. The report captures what was visible on the day of the inspection.
The standard also spells out what is excluded. Environmental hazards like radon, mold, asbestos, and lead paint are not covered. Neither are wood-destroying organisms like termites, the condition of buried sewer lines, or cosmetic imperfections that don’t affect how a component works.1American Society of Home Inspectors, Inc. Standard of Practice If you want information on any of those, you hire a specialist. More on which specialty inspections are worth the money later.
Structure, Foundation, and the Exterior
The inspection usually starts outside. Foundation walls get careful attention because the type of crack tells the inspector what’s happening in the soil. Horizontal cracks suggest lateral pressure pushing against the wall. Stair-step cracks in block foundations and vertical displacement point to settling or shifting. Foundation repairs run $2,200 to $8,100 nationally, and waterproofing an affected foundation runs $2,300 to $7,300, so the distinction between cosmetic and structural matters.
Roofs are checked for the condition of shingles or other covering, the flashings around chimneys and vent penetrations, and whether the gutter system actually moves water away from the house. The question underneath all of it is whether water can get into the building envelope. Siding, brick, and other exterior surfaces are checked for damage or installation failures that would let moisture into the wall cavity.
Lot grading is quieter but consequential. The ground around the foundation should slope away from the house at roughly half an inch per foot for the first ten feet.2Building America Solution Center. Final Grade Slopes Away from Foundation When soil settles toward the foundation instead, rainwater pools against the walls and eventually finds its way into the basement or crawl space. Inspectors also note whether downspouts discharge far enough from the foundation, whether window wells drain, and whether walkways and driveways have settled or become trip hazards.
Plumbing
Plumbing inspections cover visible supply and waste lines, looking for active leaks, corrosion, and problematic pipe materials. The inspector runs multiple fixtures at once to see how pressure holds up under demand. A clear drop when two faucets are open usually means undersized supply lines or a failing pressure regulator.
Water heaters get specific scrutiny. The inspector verifies the Temperature and Pressure Relief (TPR) valve and its discharge piping are present and properly installed. These components prevent catastrophic pressure buildup inside the tank. The discharge pipe must run downhill without any shutoff valves, terminate near the floor or outside, and remain unobstructed. When this piping is missing, capped, or routed improperly, the water heater becomes a genuine explosion hazard.3International Code Council. Water Heater Safety in the International Codes
Pipe material also goes in the report. Polybutylene piping, a gray plastic supply line installed in millions of homes from about 1978 to 1995, became notorious for premature failures at fittings and connections. The resulting class-action settlement covered re-plumbing for more than 320,000 homes.4Public Justice. One Really Good Class Action If your inspector finds gray, blue, or black plastic supply lines stamped “PB2110,” expect it in the report, and expect that some insurers won’t write a policy on a home that still has polybutylene in service.
Electrical
The electrical inspection begins at the main service panel. The inspector opens the cover to check that circuit breakers are appropriately sized for their wire gauges, confirms a solid grounding system, and looks for wiring defects like double-tapped breakers, where two wires are jammed into a terminal designed for one. That connection creates loose contact points that can arc, overheat, and start a fire.
Throughout the house, the inspector tests a sample of outlets for correct polarity and confirms that Ground Fault Circuit Interrupter (GFCI) protection is installed where required. The National Electrical Code requires GFCI outlets near water sources: kitchens, bathrooms, laundry areas, garages, and outdoor receptacles. Older homes often lack this protection entirely, and retrofitting is inexpensive compared to the shock and fire risk of leaving it undone.
Panels That Get Flagged on Sight
Two brands of electrical panels trigger immediate concern regardless of whether they appear to be working on inspection day. Federal Pacific Electric (FPE) Stab-Lok panels and Zinsco panels both have documented histories of breakers failing to trip during overloads, which is the one job a breaker exists to do. Testing of FPE breakers found single-pole failure rates as high as 51% to 65% at elevated loads, and one researcher estimates these panels may be responsible for roughly 2,800 fires per year. A New Jersey court found in 2002 that FPE had violated consumer fraud laws by distributing breakers that were never properly tested to meet Underwriters Laboratories standards.
Zinsco panels fail differently. Their breakers can melt and fuse to the bus bars during an overload, creating a situation where the breaker appears to be in the “off” position but is still conducting electricity. If your report identifies either brand, budgeting for a full panel replacement is the standard recommendation. These panels don’t degrade gradually. They fail silently and unpredictably.
Heating and Cooling
The inspector tests the furnace or boiler using the thermostat, confirming it fires up, produces heat, and shuts down properly. The heat exchanger gets visual attention for cracks. That component separates combustion gases from the air circulating through the house, and a crack can leak carbon monoxide into your living space. Carbon monoxide is colorless and odorless, so a compromised heat exchanger doesn’t announce itself. Air filters are checked both for condition and as a clue to how well the previous owner maintained the system.
Air conditioning has a testing limit worth knowing about. Most inspectors won’t run the compressor if outdoor temperatures have been below roughly 60 degrees Fahrenheit for the preceding 24 hours. Operating the unit in cold weather can damage internal components, and no inspector wants to break something during a test. If you’re buying in late fall or winter, you may not get a functional AC test. Ask the inspector what conditions were on the day of the visit and whether a follow-up makes sense.
Visible ductwork is checked for separations and heavy dust that could restrict airflow. The inspector records the manufacture date from the unit’s data plate to estimate remaining life. HVAC replacement now runs $7,500 to $15,500 for a standard residential home, so the age and condition of existing equipment matter to your purchase math. Inspectors also check for secondary drain pans and emergency shut-off switches on units installed in attic spaces, where a leak could soak the floors below.
Interior and Attic
Inside the home, the inspector looks for signs of structural movement and past water damage. Ceiling stains could mean a roof leak, a failed plumbing fitting, or condensation from improperly vented bathroom fans. The inspector operates a sample of windows and doors to confirm they open, close, and lock without binding. Sticking doors or windows with cracked frames sometimes indicate foundation settling rather than a hardware problem. Windows are also checked for failed thermal seals, which show as persistent fogging between the panes.
Stairways get safety checks. Guard openings, including baluster spacing, must be tight enough that a four-inch sphere cannot pass through, a standard set by the International Residential Code to prevent small children from getting stuck or falling through. Handrails need to be securely attached and graspable.
The Attic
The attic is a window into the home’s thermal performance and some hidden conditions. Inspectors measure insulation depth and compare it to the R-value recommended for the local climate zone.5Department of Energy. Insulation Insufficient insulation drives up energy costs and can contribute to ice damming in cold climates. Bathroom exhaust fans are checked to confirm they vent to the exterior rather than into the attic itself. Dumping moist air into the attic is a recipe for wood rot and mold on the roof sheathing and rafters. The inspector also evaluates soffit, ridge, and gable ventilation to confirm air can circulate under the roof deck.
Built-In Kitchen Appliances
Permanently installed kitchen appliances that convey with the home are included. The dishwasher runs through a short cycle so the inspector can check for leaks at the supply connection and proper drainage. Oven and range burners are tested through normal controls. Garbage disposals get run to listen for seized motors or grinding that suggests damage.
One safety item inspectors specifically look for: freestanding ranges must have an anti-tip bracket installed, either behind the unit or anchored to the floor. Without it, a child climbing on an open oven door or a heavy pot placed on the front burner can tip the entire range forward. ANSI and Underwriters Laboratories have required ranges manufactured after 1991 to support 250 pounds on an open door, and manufacturers require the bracket to be installed.6Consumer Product Safety Commission. Free Standing Kitchen Ranges Missing anti-tip brackets are one of the most common findings. Built-in microwaves are checked for basic heating function and secure mounting. Portable appliances like standalone refrigerators are not part of the inspection unless the sales contract specifically includes them.
What Inspectors Don’t Look At
The items below fall outside the standard scope but can easily cost more than everything the general inspector finds combined. Whether you need any of them depends on the property’s age, location, and what the general inspection surfaces.
Radon
Radon is a naturally occurring radioactive gas that seeps into homes through foundation cracks and accumulates in enclosed spaces, especially basements. You can’t see it or smell it, and long-term exposure is the second leading cause of lung cancer in the United States. The EPA recommends installing a mitigation system if your home tests at or above 4 picocuries per liter (pCi/L), and suggests considering mitigation at levels between 2 and 4 pCi/L since there is no known safe exposure level.7U.S. Environmental Protection Agency. What is EPAs Action Level for Radon and What Does it Mean A test during the inspection period typically costs $150 to $250. A mitigation system runs roughly $400 to $5,000 depending on the home’s layout.
Termites and Other Wood-Destroying Organisms
Wood-destroying organism (WDO) inspections are separate from the general inspection but frequently required by lenders. VA loans require a WDO inspection in more than 30 states and in specific counties within several others.8U.S. Department of Veterans Affairs. Local Requirements FHA and conventional loans may require one too, depending on the region and the appraiser’s observations. In areas where termite activity is common, the $75 to $150 cost is worth it even without a lender requirement. Treatment for an active infestation averages around $600 but can reach $3,000 for severe cases, with structural wood repairs adding $600 to $6,000 on top.
Sewer Lines
A sewer scope sends a small camera through the lateral sewer line from the house to the municipal connection or septic tank. It can reveal root intrusion, collapsed sections, bellied pipe that traps waste, and deteriorating materials like Orangeburg pipe that was never meant to last more than a few decades. A sewer scope typically runs $300 to $700 and is especially worthwhile on homes built before 1980, homes with large trees near the sewer line, or any property where the general inspector noticed slow drains. Sewer line replacement can run $5,000 to $20,000 or more depending on depth and length.
Mold and Asbestos
If your general inspector notes visible growth that looks like mold, or mentions materials likely to contain asbestos (common in insulation, floor tiles, and pipe wrapping in homes built before the 1980s), a specialist is the next step. General inspectors are not required to identify mold species or test for asbestos.1American Society of Home Inspectors, Inc. Standard of Practice Mold testing usually costs $300 to $600, and asbestos testing runs $200 to $800 depending on how many samples are needed.
Lead Paint in Pre-1978 Homes
If the home was built before 1978, federal law requires the seller to disclose any known lead-based paint hazards and provide an EPA pamphlet on the risks. You also have a 10-day window to conduct a lead paint inspection or risk assessment at your own expense.9U.S. Department of Agriculture Forest Service. Lead-Based Paint – Disclosure of Known Hazards This is separate from the standard inspection. A general inspector will note peeling or deteriorating paint in older homes, but confirming whether that paint contains lead requires specialized testing.
Using the Report
The report itself is just information. Reports usually sort findings into maintenance items (dirty filters, worn weatherstripping) and significant defects (foundation movement, active roof leaks, electrical safety hazards). Focus your negotiation on the significant defects. Asking a seller to fix a squeaky hinge weakens your position when you also need them to address a failing roof.
You have three main options for the significant findings: ask the seller to make repairs before closing, request a credit toward closing costs so you can do the work yourself, or negotiate a price reduction. Closing credits are often the better play. When sellers handle repairs, they have every incentive to hire the cheapest contractor available, and you have limited ability to supervise the work. A credit puts you in control of the contractor, the timeline, and the standard.
If the seller does agree to make repairs, have your inspector return for a re-inspection before closing to verify the work. Ask for receipts showing licensed professionals did the work. A final walk-through within 24 hours of closing is your last chance to confirm the home’s condition matches what was agreed. If agreed-upon repairs weren’t done, raise it with your agent before anything gets signed at the closing table.