Seattle Home Inspection: What Inspectors Actually Check

A standard home inspection in the Seattle area takes 2–4 hours and covers the visible, accessible condition of the home’s major systems: structure, roof, exterior, plumbing, electrical, heating, insulation, and interiors. It does not cover everything — and the things it excludes are exactly the things that bite buyers of older Seattle homes hardest. Here’s what’s actually on the inspector’s list, what isn’t, and what to add.

What’s in scope (and what isn’t)

Washington licenses home inspectors and sets standards of practice for what a general inspection covers. The short version: an inspector evaluates what they can see and safely reach on the day of the inspection. They don’t open walls, move the seller’s furniture, or dismantle equipment.

Commonly excluded — order these separately if they apply:

• Sewer scope. A camera run through the side sewer. Essential for older Seattle homes — see why in our sewer scope guide.
• Oil tank search. Many pre-1970s Seattle homes once heated with oil; decommissioned (or forgotten) underground tanks are a real local issue.
• Pest/structural specialist reports, chimney interior scans, and full HVAC teardowns. The general inspector flags symptoms; specialists diagnose.

The room-by-room checklist

Roof and attic

• Roof covering condition and remaining life. Why it matters: Seattle’s wet climate plus shade trees means moss, and moss shortens roof life.
• Flashing, gutters, and downspouts. Most “mystery” basement water in Seattle starts as a roof-drainage problem.
• Attic ventilation and insulation. Poor ventilation in our damp climate shows up as condensation and mold staining on the sheathing.

Structure and foundation

• Foundation cracks, settling, and post-and-beam condition. Inspectors distinguish cosmetic hairline cracks from movement patterns.
• Earthquake readiness signals. A general inspector won’t certify seismic safety, but they’ll often note whether an older home appears bolted to its foundation — common follow-up for pre-war Seattle housing stock.
• Crawl space moisture. Standing water, damp soil, missing vapor barriers. In Seattle this is one of the most frequent findings, period.

Exterior and drainage

• Grading and surface drainage. Soil should slope away from the house. On Seattle’s many sloped lots, it often doesn’t.
• Siding, trim, and paint. Especially rot at trim joints and where decks attach to the house.
• Decks, porches, retaining walls. Attachment, ledger flashing, and rail safety.

Plumbing

• Supply and waste pipe materials. Galvanized supply lines (common in older homes) corrode from the inside; inspectors note them as near-term replacement candidates.
• Water heater age, condition, and seismic strapping. Strapping is a standard safety note in Washington.
• Fixtures, drainage speed, visible leaks. Slow drains can hint at the side-sewer problems a scope would confirm.

Electrical

• Panel type, capacity, and workmanship. Certain older panel brands get flagged by name; so do double-tapped breakers and DIY work.
• Knob-and-tube and ungrounded wiring. Pre-1940s Seattle homes frequently still have some. It matters for safety and insurability — some insurers balk.
• GFCI/AFCI protection in kitchens, baths, and bedrooms by current standards.

Heating and cooling

• Furnace/heat pump age and operation. The inspector runs it and checks visible components, not internal heat exchangers.
• Venting and combustion safety for gas appliances.

Interior

• Windows (failed seals show as fogging — very common in 1980s–90s vinyl), doors, floors, stairs, rails.
• Bathrooms and kitchens for leaks, caulking, ventilation. Bath fans that vent into the attic instead of outside are a classic Seattle find.
• Moisture staining anywhere — ceilings, window sills, basement walls. Inspectors here carry moisture meters for a reason.

The Seattle-specific shortlist

If you remember nothing else, these are the findings that most often reshape a deal locally:

1. Water management — roof drainage, grading, crawl space moisture.
2. Side sewer condition — not in the standard inspection; scope it.
3. Old electrical — knob-and-tube, undersized panels.
4. Galvanized plumbing nearing end of life.
5. Buried oil tanks on older lots.

How to use the report

A 40-page report with 60 line items is normal and not a reason to panic. Sort findings into three buckets: safety/structural (negotiate or walk), deferred maintenance with a price tag (negotiate), and cosmetic noise (ignore). If you’re competing in a hot segment where buyers waive contingencies, read our take on the inspection contingency in a bidding war before you decide what to give up — and sellers weighing whether to get ahead of all this should read about pre-listing inspections.

Attend the inspection if you possibly can. The last 20 minutes — the verbal walkthrough — is worth more than the PDF.

One more checklist item: know what your agent costs

Inspection day is where a good agent earns their fee — and where the difference between agents shows. If you’re still assembling your team, Manaky Homes is a free marketplace where Greater Seattle agents publish their fees side by side, so you can compare cost and service before you commit. Join the waitlist for early access, and try our calculators while you’re at it.