Egress Window Well Size and Ladder Rules

When a well is required

The model code allows a window sill no higher than 44 inches above the floor. In a basement the sill is often below the outside ground level, and the code says where a sill is below grade it must be provided with a window well. The well is what lets a person stand outside the opening, and what lets a firefighter in protective gear reach in. It is a separate rule from the window size (see the size rules).

The well numbers

These come from the Minnesota Department of Labor and Industry fact sheet, which reproduces the model code's R310.2.3 as adopted in that state (it describes the 2018 International Residential Code). We did not retrieve the 2021 well section itself, so confirm the numbers, and the well depth at which a ladder is required, with your permit office (Minnesota DLI, emergency escape fact sheet (reproduces 2021 IRC R310.2)).

Why the well is often the hard part

The code says the well must let the opening open fully, so a window that swings out needs more clear space in front of it than one that slides. The 36 inch projection and the clear swing together set how far the well sits from the wall. Many existing wells are smaller than that. If a basement already has a small window with a shallow well, replacing the window may also mean enlarging the well, and that is excavation along the foundation.

Safety details

• The opening must work from inside without keys, tools or special knowledge.
• Window opening control devices on a required opening must comply with ASTM F2090.

Digging outside

Cutting a window well is excavation. J.U.L.I.E. is not needed for an interior basement finish, but the one local page that mentions egress excavation, the Village of Durand's, says to call J.U.L.I.E. at 811 before digging (Village of Durand, Building and Zoning).

Permit, cost and where to start

A new egress opening in an existing foundation is permitted work. Winnebago County lists an egress window permit at $30.00 each plus a $40.00 processing fee. Cost depends heavily on how much digging and concrete cutting the wall needs; $2,000 to $5,000 each (HomeGuide, national, updated February 6, 2026) is HomeGuide's installed range. See the egress window cost guide.

Choosing a well material

Wells come in corrugated steel, plastic and poured or block concrete. The sources we read do not compare them on cost or durability, so we cannot rank them. What the code asks of every one is the same: the clear horizontal area, the projection from the wall, room for the window to open, and a way for a person to climb out. Ask your installer for the interior dimensions of the well they propose, not the outside dimensions of the product. A catalog well that is 36 inches wide on the outside can be narrower inside.

Keeping the well from becoming a water problem

A well is a hole beside the foundation. If it fills with water it can leak around the window and into the basement. EPA's mold guidance says to provide drainage and slope the ground away from the foundation, and the same principle applies to the well: ask the installer how the bottom drains, whether it ties to the footing drain, and what cover is proposed. A cover must still allow the window to be used as an exit, so ask your permit office whether a cover is allowed and how it must operate.

Plan the well before the finish so that the interior framing around the window leaves a clear path. See the stages guide.

Where to go next

This guide sits under Egress windows. Every price on this site, with its source and date, is on the basement finishing cost page. If this topic is on your list, these guides cover the neighbouring questions: Basement Egress Window Requirements in Illinois, Basement Egress Window Cost in Illinois, and What Makes a Basement Bedroom Legal in Illinois?.