How to fix a window well leak

Q: I live in a townhouse in Gaithersburg, Maryland, built in the early 1980s. It has a finished basement with a small egress window with a rounded well outside. During heavy rainstorms, which we've had many of this summer, this well fills with water and leaks through the window, even after I replaced it. I have a plastic cover over the well and even have large bins around it to try to divert water, but at a certain point when the ground is saturated, the well begins to fill from the bottom. I have to physically bail out the water, usually as rain is pouring down around me. I've had to replace the basement drywall twice because of mold, and I got rid of the carpet. The basement is not used or set up to be used as living quarters. Could I just get rid of the window (and well), as it really is not a means of escape and does not provide much light or ventilation? Or is there another solution?

A: Legally, you might be able to seal off the window because the requirement for basement egress windows did not appear until the 1997 code cycle, said Greg Dennison, permits coordinator for the Gaithersburg Planning and Code Administration. "However, depending on when the basement was finished or if the room is being used as or was designed as a bedroom (with a closet, door and smoke alarm) it would not be permitted nor recommended," he said in an email.

The key issue is whether a window was required by the building code in effect when your townhouse was built - or when the basement was finished, if that was done later. Dennison is working from home these days because of the pandemic and doesn't have access to older codes to see what was required in 1980. However, he guesses that if your townhouse was built with an unfinished basement, the window was intended just for ventilation and light, not egress. "If the basement was finished in let's say 1997 then that code would take precedence and the window would be required," Dennison wrote. If the basement was finished without a permit, you might be able to establish the date by examining the materials that were used, such as wire, drywall or fixtures. "Most construction materials are dated," Dennison said.

Gaithersburg uses the 2018 International Residential Code. It requires an egress window in each basement bedroom unless the dwelling has fire sprinklers and another part of the basement has a door or egress window to the outside. To meet code, egress windows need to be considerably larger and more elaborate than what you have now because it isn't likely someone in a rush to escape a house fire could boost themselves up and squiggle out through a window as skinny as yours. Egress windows that meet today's requirements have to provide 9 square feet of opening - large enough for a firefighter carrying safety gear in a backpack. The window has to open without tools, its base can't be more than 42 inches from the floor, and there must be a ladder or other way for someone to get from the window well to safety.

Even decades ago, when builders installed window wells, they usually took care to deal with underground water. "Typically window wells have a drain that is connected to the foundation drainage system or drains to daylight somewhere in the yard," Dennison said. "Over time that drain could become clogged and could possibly need to be cleaned out."

Suspect a clogged drain, especially if your window well didn't used to fill with water as it does now. But figuring out where the drain connects isn't always simple. Check whether your townhouse association has plans that show this detail. If not, and if there is a slope, investigate whether a downhill area gets wet in rainstorms from a gutter or drain pipe that could be emptying there. Otherwise, trying to find a clogged drain might mean excavating the window well down to the bottom of the foundation, where the drain tile for your building should be.

Brandon Thompson, sales manager for JDS Home Improvement, a Gaithersburg construction company that specializes in egress windows, said excavating a window well and making the fixes that will keep water from collecting could cost $4,500 to $5,500. "We would remove the existing window well," he said. "We'd bring an excavator in and dig down to the footer." There is no way to address the problem otherwise, he said. "We have to go down to the source, to see what is wrong with the drainage."

If you wanted to upgrade your window to one that qualifies as an egress, the cost would be $6,500 to $7,000, Thompson estimated. Given how much it would cost to redo your current window, the upcharge may be worth it because it would give you - or future owners - more options for how to use the basement.

David Arias, owner of Drainage & Erosion Solutions in Falls Church, Virginia, said the pictures you sent appear to show the window well has sunk and that nearby soil slopes toward the house, probably because of soil settling and erosion. He'd inspect to make sure, then send in a crew to dig out the window well and reposition it, which might require adding another section. They'd also regrade so that water flows away. Those steps, plus a tight cover, should fix the problem for around $3,000 to $5,000, he estimated.

Arias said adding a drain pipe isn't usually possible because most lots don't have a good place for the water to empty, other than piping it inside the house, which is not ideal. But as a last resort, both he and Thompson said, the company could install a sump pump in the window well. That would save you from having to bail out the water by hand. Yet it would protect your basement only as long as the power stays on.

You may also want to consider improving drainage issues near your house and then seeing if that's enough to keep the window well dry. The code requires at least six inches of drop in the first 10 feet out from a foundation, Dennison noted. But he said he's seen numerous cases where the material that was used to backfill around a foundation gradually settled, causing the surface to slope toward the house, rather that away from it. Filling in the depression with mulch doesn't change the way the water moves; the fill should be a low-porosity soil, such as clay. Using bins as water diverters still lets water flow through the gaps. Figure out a way to keep water from flowing there, such as by extending gutter downspouts or by building a swale that diverts surface flow.