What a Home Inspection Covers (and What It Misses)

A standard home inspection covers visible, accessible components -- structure, roof, electrical, plumbing, and HVAC -- but does not open walls, inspect sewer lines, or certify code compliance. The American Society of Home Inspectors puts typical cost at $300 to $500 and inspection time at two to four hours. What the inspector misses matters as much as what they find.

What the Inspector Actually Examines: Structure, Roof, and Exterior

A licensed inspector evaluates condition from the ground up, starting with the foundation and framing -- where failure is most expensive to correct.

At the foundation, the inspector looks for visible cracks, settling, water staining, and prior patching. Not every crack is structural -- hairline shrinkage cracks in poured concrete are common -- but horizontal cracks in block walls, stair-step cracking in brick, or gaps at the sill plate warrant attention. Costs vary by scope: minor crack injection runs $500 to $1,000, while full underpinning or pier installation can reach $10,000 to $30,000 or more, according to Angi's 2024 cost data.

Moving outward to framing, walls, and cladding, the inspector notes whether the roofline sags, walls are plumb, and siding shows cracking or moisture intrusion. Ground clearance matters: siding less than six inches from the soil line is a common pathway for moisture damage and termite entry.

The roof is assessed from the exterior -- shingle condition (granule loss, curling, missing pieces), flashing at penetrations and valleys, gutters, and the chimney where accessible. Inspectors do not walk a roof when pitch or condition make access unsafe; assessment is then from the ground or at the eaves. If the roof is steep or aging, a separate evaluation by a licensed roofing contractor is worth the cost before you proceed.

Inside the attic, the inspector checks insulation depth, ventilation (ridge, soffit, and gable vents), rafter or truss condition, and signs of roof deck damage, moisture staining, or daylight. Poor ventilation is common in older homes and contributes to premature shingle degradation, higher cooling costs, and moisture accumulation.

What the Inspector Examines: Electrical, Plumbing, and HVAC

The mechanical systems -- electrical, plumbing, and HVAC -- are the bulk of a home's operational infrastructure. A thorough inspector covers what is accessible.

Electrical. The inspector evaluates the service entry, main panel, and accessible wiring: amperage (many older homes have 100-amp service; modern homes need 150 to 200 amps), double-tapped breakers (two wires on one breaker, a code violation in most jurisdictions), aluminum branch wiring from the late 1960s through the 1970s (a fire risk), and GFCI protection in wet areas. They do not inspect inside conduit or behind finished walls.

Plumbing. The inspector runs fixtures, checks visible supply and drain lines, evaluates the water heater's age and venting, and looks under sinks for leaks. They note pipe material where visible: copper is standard; galvanized steel in pre-1970s homes corrodes from the inside, reducing pressure and eventually failing; polybutylene (gray, installed roughly 1978 to 1995) has a known failure history and is generally recommended for replacement.

HVAC. The inspector runs heating and cooling through a basic operational test -- confirm conditioned air, note unusual sounds, check filter and accessible ductwork. They estimate equipment age (furnaces typically last 15 to 20 years; central air conditioners 10 to 15 years, according to InterNACHI) and flag visible deterioration of heat exchangers, flue venting, or refrigerant line insulation. They do not perform deep diagnostics; for an aging system, a separate HVAC technician inspection before closing is worth it.

The table summarizes common findings, not worst cases. Most inspected homes show some of these -- the question is whether they are material to your decision and negotiation.

What the Inspector Does Not Check -- and Why It Matters

This is the section buyers most often skip. A general inspection has well-defined limits by design, and understanding them determines which additional inspections to order.

Behind walls, under floors, and inside ceilings. An inspector works from visible surfaces and cannot see inside a wall cavity without destructive testing. Hidden plumbing leaks, mold behind tile, deteriorated wiring in conduit, and insulation voids go uncaught. If surface evidence suggests a problem -- staining, soft flooring, a musty odor -- the inspector can flag it but cannot quantify what they cannot reach.

Underground sewer lines. The gap that surprises buyers most. A standard inspection excludes a sewer scope -- a camera inspection of the lateral line from the house to the municipal connection. Yet it is among the costliest repairs: replacing a deteriorated cast-iron or clay lateral can cost $4,000 to $25,000 depending on depth and length, according to HomeAdvisor. Cast-iron lines installed before 1975 are especially prone to scale buildup and collapse. A separate scope typically costs $150 to $300 -- worth scheduling during due diligence on older properties.

Mold and air quality. Unless the inspector sees conditions strongly suggesting mold -- visible staining, significant moisture intrusion, documented water damage -- testing is outside the standard scope and needs a separate contractor and lab fees. If the report notes water intrusion in a basement, crawl space, or attic, a mold assessment before proceeding is reasonable.

Active pest infestations. Inspectors note wood damage consistent with termites or beetles, but a full pest inspection (a Wood-Destroying Organism or WDO inspection) is a separate service by a licensed pest professional. Many lenders require one. Cost is typically $75 to $150.

Chimney interiors. An inspector evaluates the visible exterior and firebox but does not sweep or run a Level 2 camera inspection inside the flue. The National Fire Protection Association recommends annual inspection of chimneys in regular use. For a wood-burning fireplace or stove, a Level 2 inspection by a Chimney Safety Institute of America-certified sweep is worth the cost before your first fire.

Septic systems, wells, and outbuildings. Private septic systems need a separate inspection (typically pumping and load testing) running $300 to $700. Private wells need water quality testing for coliform bacteria and pH at minimum, plus local contaminants by region. Detached garages, sheds, and outbuildings are outside the scope unless you specifically request inclusion.

Specialty Inspections Worth Considering

Depending on the property's age, location, and the general report, specialist inspections can close the gaps a standard assessment cannot reach.

Radon. A radioactive gas that enters through foundation cracks, radon is the second leading cause of lung cancer in the United States, according to the U.S. Environmental Protection Agency. Short-term kits cost $15 to $30; professional testing runs $100 to $150. The EPA recommends mitigation at or above 4 picocuries per liter, with systems typically costing $800 to $2,500 installed, according to the EPA. Many buyers in the Midwest and Northeast test routinely regardless of the general report.

Sewer scope. Covered above. Prioritize it if the home is over 30 years old, has large mature trees near the property line, or sits in an area with known cast-iron infrastructure.

Lead paint and asbestos. Homes built before 1978 may contain lead-based paint; those before 1980 may have asbestos in insulation, floor tile, shingles, or pipe wrap. A general inspector may note suspect materials, but testing requires a certified inspector. HUD recommends lead paint testing on pre-1978 homes, particularly when children will live there.

Pool and spa. A full pool inspection covers pump and filter operation, plumbing integrity, structural condition, and safety compliance -- beyond the visible deck and equipment a general inspector glances at. Repairs can be substantial: resurfacing costs $3,500 to $10,000, and plumbing or equipment failures add several thousand more, according to HomeAdvisor.

Structural engineer. If the inspection uncovers foundation movement, signs of structural modification (an apparently removed load-bearing wall, an undersized header), or severe wood rot, an independent structural engineer gives a professional opinion on remediation scope and cost. A consultation typically costs $300 to $700.

The Inspection Contingency: What It Does and What Happens When You Remove It

The inspection contingency is a contract clause that lets you exit, or negotiate repairs or a price reduction, based on a professional inspection. Without it, you have no contractual basis to revisit the price or back out without losing your earnest money deposit.

The window is defined -- typically five to ten business days from accepted offer, varying by state and local practice. During it, you order the inspection, review the report, and decide whether to proceed as-is, request repairs or a credit, or exit. Take no action and the contingency expires; you are bound to the original terms.

What the negotiation yields depends on the report and the market. In a buyer's market, sellers routinely repair items, cut the price, or credit at closing. In a competitive seller's market, they often offer little or nothing, citing other offers. The contingency does not force a seller to fix anything -- it gives you the option to walk away if they will not.

A repair credit at closing is often preferable to having the seller complete repairs. If the seller hires the cheapest contractor and you cannot verify quality before closing, you inherit both the work and its deficiencies. A credit lets you control who does the work.

For how contingencies fit the overall offer and contract process, see How to Buy Your First Home: A Step-by-Step Guide.

Inspection costs and any resulting credits are part of your total acquisition cost. See Closing Costs Explained: What Buyers Actually Pay for a breakdown of the full cost structure at the table.

Reading the Inspection Report: Prioritizing What Matters

A full inspection report on an older home can run 40 to 80 pages, and the length alone can be alarming. Most of it documents minor maintenance and normal wear; the skill is telling what needs immediate action from what does not.

Inspectors describe condition, not cost -- they do not assign dollar values or say "deal-breaker" or "walk away." Those judgments are yours, made with your agent and, when warranted, specialists. A practical approach is to sort findings into three categories:

Category 1 -- Safety and major systems. Anything flagged as a safety issue (exposed wiring, dead smoke detectors, carbon monoxide hazards, structural concerns) or affecting a major system (HVAC that failed to run, a water heater past its life, active basement water intrusion). These drive the negotiation or the decision to exit.

Category 2 -- Material defects with cost implications. Not safety-critical but meaningful if deferred: a roof with two to three years left, a furnace at year 18 of a 20-year lifespan, polybutylene supply pipe throughout. These should factor into your price negotiation or contingency response.

Category 3 -- Maintenance items. Caulking to refresh, gutters to clean, a dryer duct to reroute outside, grading to direct drainage away from the foundation. These are ownership tasks, not defects -- a list of 20 to 30 is normal for any lived-in home.

Your agent helps you understand which items typically get negotiated in your market and which sellers resist. If any Category 1 or 2 finding needs a specialist to quantify -- a structural engineer, an HVAC technician, a plumber to scope drain lines -- use the remaining days in your window for that second opinion. Most sellers accommodate reasonable scheduling.

The inspection is one of the last information-gathering steps before you commit. The $300 to $500 fee does not guarantee a defect-free property -- it buys professional eyes on the visible structure and systems of what may be the largest purchase of your life. Use it, read it carefully, and follow up on what it cannot reach.

For a complete walkthrough from offer to close, see How to Buy Your First Home: A Step-by-Step Guide.