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Today, while in the crawl space under the house, I found a large hole that has water in it. Now I'm trying to figure out what to do about it.

I had noticed a depressed area under the house in the past, possibly starting four or five years ago. Since I rarely go under the house, I didn't pay much attention to it; but, over the last year I'd noticed it was larger.

Today, I thought I would fill it in with some old concrete block pieces. That's when I realized how big a hole it is. It's about 4' wide. And, it about 3' deep.

I hooked up a light and took a picture (below) and discovered that there are spiral steel/iron rings in the hole. The rings appear to be three or four feet in diameter. The water is cloudy, but there's no smell. And, there is no perceptible movement of the water. The photo doesn't show the water; but, it's maybe 3' deep.

I think this must have been a drainage pipe built before our subdivision was constructed in the 1980's.

Anyway, it's clear that about 3 cubic feet of soil has washed away so far. So, I have to do something.

Should I phone the local county storm drainage folks and ask them to check it out? Or, is this a problem I'll need to hire a contractor for? If so, what type of contractor?

Will appreciate advice from someone with knowledge of this type of problem.

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Update 4/24/14: Received sump pump today and used it to pump out a lot of water: my guess is about 90 gallons. And, not done yet. Further, while running the water hose for the pump over to a vent another hole appeared. It's smaller, but right next to a pier. And, shining a light down in this hole, similar spiral metal coils with water below were visible. The spirals rings are on line with those in the first hole, about 15 feet away.

What I'm planning on doing is: keep pumping the water out of the first hole; move pump to second hole and repeat; dig outside the crawlspace and try to locate the water tunnel and pump it dry there too. After all water is removed, wait a few weeks to see if water returns, and from which direction. Finally, after stopping the source of the water, fill the complete tunnel with dirt. But, if anyone has any better ideas I'm flexible.

  • I'd have that scoped with a drain camera to see if it actually goes anywhere. – Handy Man Jul 24 '14 at 14:10
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Wow! What a surprise. I don't think it's related to any county storm drainage system. Wouldn't hurt to contact them though. My best guess is someone acquired some spiral reinforcing somewhere and used it to construct a dry sump for some purpose. It was then forgotten until the cover collapsed and you noticed something amiss. The water probably means you have a shallow water table.

If my assumptions are correct, you just need to fill it in. If there is no nearby foundation structure, you just need some manual labor to haul in fill material. If it is near a foundation, at least some of the fill may need to be compacted. Depending on access, this can be difficult. You could probably hire any general contractor willing to take on the job.

  • Thanks for the insight. Though I don't know what a dry sump is. You're probably right about a low water table. My house sets near the bottom on a downward sloping street. So, my guess is that the top cover collapsed and the dirt fell in. Also, maybe the water is from seepage. Anyway, first thing I'll do is see if the county will help out. – getterdun Apr 18 '14 at 1:24
  • Dry sump maybe isn't the right term. Basically a way to dispose of unwanted incidental water, such as snow melt of of vehicles in a garage. Many municipalities forbid this sort of thing to be dumped into their sewer system, and it's often impossible to bring such drains out to surface drainage due to topography. – bcworkz Apr 18 '14 at 17:15
  • No help from county. Now plan to dig in each direction to see if the water is just in this one place. – getterdun Apr 19 '14 at 6:21
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    Are you on well water? Do you know where your well is? This (albeit usually with concrete rings and lid) is a typical wellhead installation from a certain era in these parts. – Ecnerwal Apr 20 '14 at 2:44
  • To clarify and update: our home is near Charleston, SC. No well water. No sump, just a hole in the ground with water in it. No basement. Today, tried siphoning water out with water hose, but failed. So, ordered a sump pump. Plan to hook it up to a water hose and drain water out to the street. It rained 4" on Saturday and the water in the hole now covers the metal rings. – getterdun Apr 21 '14 at 2:40
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Your description of the "reinforced hole" matches that of an old well or cistern, perhaps from when the land was agricultural anywhere from the late 1930s through the 1970s.

To confirm, ask your local land use bureau, historical society, or equivalent who can produce survey maps from the mid 20th century—or any time before your house was built. Topographic and survey maps usually show wellheads and building structures if they are prominent enough.

If they do indeed confirm a well or cistern, then simply filling it in is almost certainly good enough. If the map shows a spring, you might want to install a liner and a drainage system.

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If you have a sump it is probably there for a reason - if you fill it in, then the water that is in it will instead be all over the floor of your currently dry basement. Get someone who knows about basement drainage to take a look. It's very common in Canada to have a sump in the basement, usually with a pump, hooked up to the storm drain. Google basement sump.

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That hole is a sump. Install a sump pump in it and pump the water out from house.

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