During some recent heavy rains one of my window wells filled with water, which started coming into the basement through the deteriorating window. I have a drain tile system around the interior of the basement walls but no drain around the exterior. (The house was built in the 40s, and the interior drain tile is a recent enhancement.)

In the two summers since it was installed, the sump pump has run very little. I've never actually noticed it running apart from when I test it, but the seepage I used to get on a regular basis from the bottom of the basement walls has stopped.

I'm considering installing drains in the window wells to connect to the interior drain tile. I have misgivings about intentionally channeling all that water through the inside of my house to the sump pump, though. While adding the window well drains seems like the obvious solution to keep the window wells dry, how much worse would it make a sump pump failure? Would it make a failure more likely because of the increased activity?

  • Do you have a plan for getting through/under the footings? Is there a slab inside? How much does your sump normally run?
    – isherwood
    Commented Sep 22, 2016 at 17:37
  • That use to be a rather normal design in the US. However it has issues and doesn't meet code in most places now. If it worked well it would still be code.
    – DMoore
    Commented Sep 22, 2016 at 17:39
  • I would have the same contractor that did the interior drain tile install the window well drains. I'm trying to decide if that's actually a good idea, or if I should pursue other options. For example, since the window needs to be replaced in any case, I might be able to make it entirely above-grade and do away with the window well entirely.
    – Simon
    Commented Sep 22, 2016 at 17:40
  • @isherwood I added some details about current sump activity to the question.
    – Simon
    Commented Sep 22, 2016 at 17:48
  • 1
    @DMoore Correction: If it worked well in every scenario it would still be acceptable by code. Codes are expanded to handle fairly rare problems as often as not. In this case I'd say it's a good plan.
    – isherwood
    Commented Sep 22, 2016 at 17:57

5 Answers 5


You're right on target with the questions you've asked. You want to prevent water from collecting around the house. Ideally, it's best to avoid water being there in the first place. If you can't do that, that next best solution is to give it a place to go to get rid of it as quickly as possible. That can be accomplished on the exterior or the interior. If you put in a system to get rid of water, the benefit will come from letting it get rid of as much problem water as you can get into it.

To drain the window wells, don't just drill holes and let the water run down the wall into the floor drain. Stick a pipe through the wall with the wall opening sealed around the pipe, and direct the water into the drain while keeping it contained. Use some form of screen or filter on the inlet so the pipe doesn't get clogged with debris.

As you noted, once the basement is no longer sealed, water can migrate in as well as drain out. The interior drain, itself, is a potential path, and any other exterior water you provide with a path adds to it. It is critical to have a reliable and redundant system to get rid of the water or your basement can become the collection system.

Sump pumps don't last forever, so have a second, backup pump. Power can go out in a storm, which is the likely time when water will be feeding the system. So use some form of battery backup or make one of the pumps battery- or dual-powered and include a provision for keeping the battery charged and tested. Or have the pumps on a backup generator.


It is very common for exterior drainage tiles to be connected to an interior sump. Here it is a requirement to provide drainage from window wells to the drainage tiles. Where those cannot be gravity routed to daylight, there are routed to a sump pit. Perfectly acceptable solution to your problem if your local code allows it.


We did something similar in a car wash we built. The car wash has a lube center for oil changes. The oil changing station is on the street level and the area where mechanics perform the work is in the pit, below ground (similar to where a basement would be)

The problem was when it rains there was nowhere to drain the water around the lube stations. So we had sloped the grade into a drain that went into the pit where the sump pump was. This met code and resolved the drainage problem and I have never heard of any problem since then. That was 7 years ago.


Wouldn't it be cheaper and more efficientjust to buy some window well covers and just deflect the water away from the home?

  • 1
    Aren't those intended more to prevent debris than water? I already have some basic covers on the window wells, but they don't help much when the ground is saturated like it was when I asked this question.
    – Simon
    Commented Jan 24, 2017 at 16:24

I've been thinking of this solution too. The water table rises up from below grade and gets to the height of the window, not from rain falling in. You only need to have the well drain just a bit lower than the window to stop the well from over flowing in emergency situations. This would limit how much water your allowing into the interior only to prevent flooding into the window itself. There may be some water left in the well, but will dissipate when the water table drops.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.