Why is my sump pump bone dry?

November 13, 2009 4:42 PM

Why is my sump pump bone dry?

My sump pump, which I am certain works perfectly well, is completely dry in the middle of a rainy November in Seattle! What the heck? We had an extremely dry summer, but for the last few months it has been a typical Seattle fall. Why hasn't the water beneath/around our house worked its way into the sump pit?

I know the pump works. I've tested it, and I've had a plumber test it. The GFI at the outlet it's plugged into was tripped for a long time during the hot summer (probably not related to pump), so it was down until the beginning of October. However, isn't that enough time for the ground to get soaked enough for water to work its way into the pit?

posted by Waldo Jeffers to home & garden (5 answers total)

what is the history with this sump.. Is it typically pumping, have you had periods in the past when it has been dry? has any drainage flows changed?

A dry sump is a good thing....
posted by HuronBob at 5:35 PM on November 13, 2009

My sump pump (also in Seattle, installed after the last round of flooding in the crawlspace a year or so ago) is running way less than I expected it to. So, not an explanation, but at least another data point. Maybe it hasn't been raining in the same pattern it was last year.
posted by hades at 6:46 PM on November 13, 2009

Here are rainfall plots for the first 12 days of November, last year and this year. Looks like last year was more constant, and this year has been a couple really heavy days. I can imagine that we'd end up with more water in the storm drains and less under our houses like that. But that's not my field, so it's just a guess.
posted by hades at 6:54 PM on November 13, 2009

If I may, I think your question really is why your sump is dry. The sump pump's job, after all, is to empty the sump.

Now, in order to answer the re-stated question, we need to know a lot more. Has your sump been filling up every year until now? How does water get to the sump? I assume there is a collection system, such as french drains or such. Do you have any reason to believe the drains are clogged? I would doubt that they would all be clogged at once. As has been pointed out above, it is likely that the rain pattern coupled with the reduced rainfall amounts has probably meant that not much water is getting to your sump. This is a good thing.

If it were my sump, I would be dancing around and celebrating. In good time, the sump will fill and you'll be paying to run the pump.
posted by Old Geezer at 8:08 PM on November 13, 2009

Have you changed any landscaping/grading near your house? had any work done to your rainspouting, or installed rain collection barrels? Sometimes all you need to keep a basement dry is adding 6 feet of pipe to the downspout of your rain gutters to move the water away from the foundation.

I second the option that a dry sump is a good thing.
posted by jrishel at 7:58 AM on November 16, 2009