The 15 Major Issues Found In Home Inspections

We analyzed thousands of inspection reports. The same 15 issues account for over 90% of repairs that exceed $2,500. Here they are, ranked by frequency × severity for 2026.

How This List Was Built

Frequency = share of inspection reports where the issue appears. Severity = median midpoint repair cost. The ranking multiplies the two. Costs reflect 2026 contractor pricing across the contiguous U.S.; expect 15–25% premiums in CA, NY, MA, and metro areas with high labor cost.

Tier 1 — Findings In More Than Half Of Reports

1. Aging or end-of-life roof (62% of reports): Median replacement: $14,500. Negotiation weight: high if under 2 yrs of life left.
2. Grading and drainage issues (58%): Regrading + downspout extensions: $1,500–$8,000. Cause of most basement water claims.
3. Aging HVAC (55%): Furnace 15+ yrs or AC 12+ yrs. Combined replacement: $9,000–$18,000.
4. GFCI/AFCI outlet violations (52%): Cheap fix ($20–$50/outlet) but flagged on nearly every report.
5. Water heater near end of life (48%): Replacement: $1,800–$3,500. Heat pump conversion: $4,000–$6,500.

Tier 2 — Major Findings In 20–40% Of Reports

6. Foundation cracks or settlement (37%): Hairline = monitor. Horizontal/stair-step = engineer eval $400–$800. Repair: $2,500–$25,000.
7. Plumbing leaks under sinks or at fixtures (34%): Per-leak repair: $150–$500. Often clusters together.
8. Insufficient attic insulation (32%): Top-up to R-49: $1,500–$4,000. Pays back in 4–7 yrs.
9. Window seal failures (29%): Per-window: $400–$900. Whole-house program: $8,000–$25,000.
10. Improper deck construction (24%): Re-attach ledger, replace flashing: $500–$3,000. Full rebuild: $8,000–$25,000.
11. Sewer line defects (23% — when scoped): Most reports skip the scope. When done, 1 in 4 finds an issue. Repair: $3,000–$15,000.

Tier 3 — Less Common, But Expensive When Found

12. Federal Pacific / Zinsco panel (8%): Mandatory replacement: $2,500–$5,000. Insurance dropdown if not addressed.
13. Polybutylene plumbing (6%): Re-pipe required by most insurers: $4,000–$10,000.
14. Active mold (50+ sq ft) (5%): Remediation $2,000–$15,000 plus source repair. Always investigate the moisture pathway.
15. Underground oil tank (4% of reports in tank-heating regions): Removal $1,500–$3,000. Remediation if leaking: $15,000–$100,000+.

What 'Major' Actually Means For Your Offer

A 'major' finding doesn't automatically mean walking away. The decision framework that produces the best outcomes weighs three things: the cost of the finding relative to the home's price (over 1.5% of price = renegotiate hard), whether comparable homes in the market have the same issue (a common regional defect carries less leverage), and your own cash reserve (if the post-close repair empties your emergency fund, the deal is structurally wrong).

Cost range

Range across all 15 major findings: $1,500–$100,000