Skip to content
CrossBeamStart a pre-check

Building Code Reference

Got a CRC R319.4 correction?

Egress window wells

For builders in California, Greater Seattle, the Las Vegas area, the Denver area and Kansas City · CrossBeam Permits

What this code requires, how to fix it, and how cities and counties review it

What this code requires

CRC R319.4 is the California Residential Code section that governs egress window wells — the below-grade enclosures built in front of basement egress windows so occupants can escape in an emergency. The well must provide at least 9 square feet of clear floor area with a minimum 36-inch horizontal projection from the window opening. When the well is more than 44 inches deep, a permanently attached ladder or steps is required so someone can actually climb out.

How to fix it

  1. Add the window well to your floor plan and site plan

    If the window well isn't currently shown on the drawings, add it. The plan-checker needs to see it on both the basement floor plan and any exterior elevation showing the egress window. A simple rectangle with labeled dimensions is enough at this stage. Mark it clearly as the egress window well and reference the detail you'll add in step 2. Missing the well entirely is the most common cause of R319.4 corrections, and a single sheet revision fixes it.

  2. Draw a window well detail showing dimensions and calculated area

    Create a detail (typically on the A-series sheets) showing the well in plan view with the following labeled dimensions: width, horizontal depth measured from the window face, and vertical depth below finished grade. Calculate the clear floor area and label it explicitly. The minimum is 9 square feet of clear area. The minimum horizontal projection from the window face is 36 inches. A 36-inch by 36-inch well gives exactly 9 square feet and satisfies both requirements. A 36-inch by 30-inch well gives 7.5 square feet and fails. Label the area calculation so the plan-checker doesn't have to do the math themselves.

  3. Check the well depth and add a ladder if it exceeds 44 inches

    Confirm the well depth on your section drawing. If the well extends more than 44 inches below the adjacent finished grade, an approved, permanently affixed ladder or steps is required by R319.4.2. Show the ladder in your detail. The ladder must be permanently fastened to the well wall, so a clip-in or removable step doesn't qualify. The ladder or steps may encroach no more than 6 inches into the required well dimensions, and must not be blocked by the window when it is open. Note the material and attachment method on the detail.

  4. Verify the egress window itself meets R319.1 and R319.2

    R319.4 governs the well, but the window it serves must also pass R319.1 (required in bedrooms and certain habitable spaces) and R319.2 (minimum 5.7 sq ft net clear opening, 24-inch clear height, 20-inch clear width, maximum sill height of 44 inches from the floor). If either the well or the window fails, the correction won't clear. Check both in the same revision pass so you don't end up with a second corrections letter addressing the window dimensions after the well is already fixed.

  5. Address any window well cover on the plans

    If you plan to use a polycarbonate or steel cover over the well, note on the detail sheet that it opens from the inside without a key, tool, or special knowledge. An automatic-locking cover or an exterior-only latch fails the egress requirement because someone escaping a fire can't stop to look for a key. Most hinged polycarbonate covers push open from inside and pass. If no cover is planned, omit this note entirely. Don't add a cover note unless it's actually part of the project scope.

  6. Write a response letter pointing to each fix by sheet number

    When you resubmit, include a response letter addressing each line item in the corrections notice. For R319.4, reference the new window well detail by sheet and detail number, state the calculated floor area, confirm the horizontal projection measurement, and note whether a ladder was added. Plan-checkers move faster when your fixes are easy to locate. A clear response letter trims the review cycle compared to resubmitting drawings without any explanation of what changed. Point to the exact sheet and detail number for every correction addressed.

Take the CRC R319.4 fix steps with you

All 6 steps in one email, so you have them on site instead of on this page.

Why you got flagged

Here's why plan-checkers flag R319.4 on corrections letters, and it's almost always one of three problems.

The most common is that the window well isn't shown on the plans at all. A contractor calls out an egress window on the basement or lower-level bedroom elevation, but the site plan and sections don't show any well. The plan-checker has no way to verify compliance, so the project gets flagged. Adding a call-out on the floor plan or a detail on the elevations sheet clears this.

The second scenario is a well that's drawn but undersized. Nine square feet sounds generous, but the minimum 36-inch horizontal projection from the window means the well can't be a narrow slot cut into the foundation wall. A well that's 36 inches wide and 24 inches deep has only 6 square feet — that fails. The well needs to be at least 36 by 36 inches to hit the 9 sq ft threshold. The geometry catches a lot of plans that look fine at first glance.

The third scenario involves deep wells without a ladder. Any well deeper than 44 inches requires a permanently attached ladder or steps. Plans often show the well dimensions but skip the ladder detail entirely. The ladder must be permanently fastened — a removable step stool doesn't satisfy R319.4 — and it can't reduce the clear width below 36 inches.

The official code

California Residential Code — Building Standards Commission adopted code page

Read the source →

Common questions

What is the minimum size for an egress window well under CRC R319.4?
The well needs at least 9 square feet of clear floor area and a minimum 36-inch horizontal projection from the window face. For a rectangular well, 36 by 36 inches (9 sq ft) is the tightest layout that satisfies both requirements. A 36 by 30 inch well is only 7.5 sq ft and fails. A 36 by 24 inch well is only 6 sq ft and also fails. Calculate from the window face outward, not from the rough framing or the foundation wall. Obstructions like drain grates that encroach on the clear area count against you. Both the area and projection minimums must be met simultaneously — a deep well with plenty of area but less than 36 inches of projection still fails.
Does R319.4 require a ladder for all egress window wells?
No, only for wells that are more than 44 inches deep. If your well is 44 inches or shallower, no ladder is required under R319.4. If it exceeds 44 inches, the ladder must be permanently attached to the well wall. A removable ladder or step stool doesn't satisfy the requirement. The ladder rungs can't project into the 36-inch clear width of the well, so plan the mounting position before finalizing the well dimensions. Wells with ladders still need to meet the 9 sq ft area and 36-inch projection minimums.
Can I put a cover over an egress window well and still pass inspection?
Yes, as long as the cover opens from the inside without a key, tool, or special knowledge. Most hinged polycarbonate bubble covers satisfy this because they push open from inside. A cover with an exterior-only latch, an auto-locking mechanism, or one that requires a tool to operate would fail the egress requirement because someone escaping can't stop to look for a key. If a cover is on the plans, add a note on the detail sheet stating it opens from the interior without tools. If no cover is planned, leave this off the drawings.
Does R319.4 apply to ADU projects with below-grade sleeping rooms?
Yes. Any sleeping room or habitable space that requires an emergency escape window must have a compliant window well when that window is below grade. ADU projects are a common source of R319.4 corrections because the original plans were drawn for an above-grade unit and the bedroom shifted below grade during design development without updating the window well detail. If you're adding a basement ADU bedroom in Anaheim or anywhere else in Orange County, build the R319.4 well detail into the first submittal to avoid the correction entirely.
How is the 36-inch horizontal projection for a window well measured?
The projection is measured from the face of the window to the outer face of the well wall. It represents the clear standing space a person needs to fully open the window and step through it. Measure from the window face, not the rough opening or the interior wall surface. Drain grates, ladder rungs, steps, or other features that reduce the clear depth below 36 inches bring you out of compliance. The full 36 inches must be unobstructed. If you have a drain in the well, make sure it sits at the base and doesn't project into the clear horizontal space.
My correction letter says the window well isn't shown on the plans. What exactly do I add?
Add a window well detail to the plans showing the well in plan view with labeled width, horizontal projection depth measured from the window face, and vertical depth below grade. State the calculated floor area explicitly. If the well is more than 44 inches deep, show the permanently attached ladder with the attachment method noted. Reference the detail on the floor plan and the affected exterior elevation. In your response letter, point to the detail by sheet and detail number, confirm the area calculation meets 9 sq ft, and confirm the projection meets 36 inches. No field work is needed before resubmittal, just the revised drawings and the response letter.

Related corrections

Check my plans for this →