Logistics of a typical home sump hole

Factual Questions
1

Hello, all–

I’ve tried the intenet for a semi-definitive answer to this question
regarding the operation and workings of a sump hole system of
a typical house. I need some help to settle a minor discussion
on this topic–please hear me out, and if someone can steer us
right, that’d be great.

Assume a basement 8 feet deep, and 20 feet each side, (400 sq ft, 3200 cu ft.) The sump hole, 2ft in diameter, about 3 feet deep, holds about 30 gallons of water. The water level usually sits about a foot from the top of the hole. The sump pump usually cycles about once an hour every day. During a storm-induced power outage, the water rises about 2 inches per hour and over the course of 6 hours, it is at the crest of the hole. So we take a 2-gallon bucket and start bailing. We take 50 buckets, over 100 gallons out, and the water level only goes down an inch or two.
But again, it takes several hours for the water to get to the crest again.

I have several questions and observations:

  1. If we don’t bail, within next couple of hours after the water reaches the crest of the hole, will the entire basement fill up with an inch of water? Or will only several gallons come in, putting a thin layer over that corner of the basement? Is there an equilibrium threshhold that will be breached and the water will come rushing in at a greater pace?
  2. I’d assume our water table around our house is only about 4 feet below ground level, meaning our house sits in about 3 feet of saturated clay. Is this unreasonable? Would our basement have 3 feet of water in it every day, then? There’s pore space that hold the water in the clay, and the way the basement and sump hole are designed, water and air pressures keep the water
    from caving in or rushing into the basement…right?

Now of course, some people get basements with 6 feet of water,
or, in this case, about 9000 gallons of water. If my thinking weren’t flawed, it would have taken 180 hours to fill up the basement, which is probably untrue, considering our neighbors
5 doors down filled theirs and we didn’t.

Did it matter that we bailed? Like I said, our sump hole never got over the crest and our power came back on about 18 hours later.
My wife maintains we would have had three or four inches of water over the entire basement. I maintain it might have been
the hundred gallons we bailed or so, putting a thin layer at best
over some of the basement floor.

Sorry if the question cannot be answered with the info I’ve
given.

Thanks.

Bill Priester
Mergle

2

I’m sorry, I’m having trouble grasping what your exact question is, I’m so distracted by horror at the scope of the water problem you have.

Where is your house built, anyway? Right next to a swamp, or what?

Are you just asking how much water would have come in if you hadn’t bailed?

Answer: too much.

Me, I’d consult a sump pump professional.

Or move.

To a house on higher ground.

:smiley:

3

Just estimating from my sump pump specs and how much it runs I’d say it pumps out 100 gallons per hour during a sustained rain. Once all the pipes under and around the basement are full I’d expect that 100 gallons per hour to flow into the basement once it’s crested over the crock. In a 20’ square basement that’s about an inch every 2 1/2 hours assuming your floor is level. I’m sure there are other factors involved but I don’t think they can be factored in easily. If you’re really worried about it you can get a battery powered backup pump or a generator.