Egress Window Requirements for Idaho Basement Bedrooms

If you’re finishing a basement bedroom in Idaho, the room needs an egress window. This is enforced. Here’s exactly what’s required and what it costs.

Idaho code requirements (IRC R310)

• Minimum 5.7 sq ft of clear opening (5.0 sq ft for grade-floor openings).
• Minimum 24″ clear height and 20″ clear width.
• Maximum 44″ sill height from finished floor.
• Window well required if sill is below grade. Minimum 36″ projection, 9 sq ft area.
• Permanent ladder required in window wells deeper than 44″.
• Operable from inside without keys, tools, or special knowledge.

Install cost in Eastern Idaho (2026)

• Cut concrete + install + window well + window: $3,500–$6,500
• Above-grade existing rough opening (just window swap): $1,200–$2,400
• Steel window well with stairs: $400–$900
• Composite/landscape well: $600–$1,400

Workarounds that don’t work

• “It’s a bonus room, not a bedroom.” Inspectors call this. A closet plus a door makes it a bedroom.
• “I’ll just call it an office.” Same problem if there’s a closet.
• “The existing window is close enough.” If it doesn’t hit 5.7 sq ft clear, it fails.
• “I won’t pull a permit.” Insurance won’t cover a fire fatality in a non-permitted, non-egress bedroom. Don’t.

Bonneville and Jefferson County process

Both counties require a permit for egress install. Plan review takes 3–7 business days. Final inspection happens after install. Budget 2 weeks total from permit pull to passed inspection.