Water level under house?

[Howie]

I have water entering my sump pit at a point 8" below the basement floor. The flow of this water is relatively strong after a heavy rain and typically takes at least five days to reach a point where it no longer seeps in at this point. I might note the water table is unnaturally high in this area due to much above average precipitation over the last four months.

The perimeter drain at my house sits on top of the footers and I have been advised by the builder this positioning places the perforated drain tile 4" below the basement floor. This drain tile is connected to a hard PVC drain pipe and drains to daylight behind my house.

My question...theoretically speaking as I am reticent to unplug my sump pump and test this particular theory... if my sump pump were not working and the water level rose-- would the water level rise across (under) the entire basement floor area and find its way into the perimeter drain before attempting to enter into the floor, under the walls, etc.?

I find that rain water near my house not removed by gutter downspouts and the exterior grading is finding its way under my footers, bypassing the perimeter drain, and eventually into the sump pit. I understand the perimeter drain is there to primarily capture rising ground water, but I was surprised recently during a heavy rainfall that no water was exiting the aforementioned drain pipe. I dug down where it is connected to the perimeter drain, rain a hose onto that area, and the water ran down the drain pipe. Why rain water is not entering the perimeter drain initially is somewhat confusing, but perhaps the chosen positioning of this drain tile (on top of the footers vs. along side) might have something to do with the fact rain water seems to be aggregating into the water table and finding its way under my basement.

Sorry for the digression... and thanks for your thoughts regarding what should happen if my sump were not functioning relative to the water level rising and potentially finding the perimeter drain before finding my basement.

--Howie

[EXT]

Very likely you are correct, especially if you have porous soil that the water can easily travel through. In most areas that I am familiar with the perimeter drain empties into the sump, and then is pumped out. If your perimeter drain exits to an area below the foundation, why was there a need for the sump.

An other thought, does it really drain to below the foundation or is water standing at the exit and is deep enough to run back up the pipe to flood your sump (or possibly the same water being circulated). Or possibly the exit pipe is blocked with an animal nest or dead animal preventing the water from leaving. You should not have an open pipe, check to ensure it is screened or that the screen is still in place.

[Howie]

Thanks for the comments.

The sump was installed as it was actually a requirement of the developer that all homes in this particular subdivision- with a basement- have a sump pump installed.

The drain pipe (the one attached to the perimeter drain and running to daylight) has a gate-type device near the end to prevent critters from getting in. I checked the entire length of the drain pipe and it was clear of any obstruction.

[Bewildered]

It all depends. My old house did just that; it rose evenly until it reached the floor level. Until we had an actual flood, and then everything changed for the worse. It would actually flood one corner while it was still low at the sump corner. I had to put a second sump pump in at the second corner. I thought the drains were clogged, but called the original owner and found out there were no drains! The basement flooded at every rain, so they installed a sump pump but no drains.

So, my experience may not be useful to you. A couple months ago we had so much rain that I actually got water in the bottom of my sump for the first time ever at my new house. Not enough to trigger the pump, but some water. I am much happier at the new house.

[Bob M.]

Two things, but only one is practical.

The practical one is to make your downspouts run as far away from the house as possible. I have one that extends out about 8 feet. I took it off just to see if I really needed it. It rained pretty good after that and I ended up with an inches-deep puddle right there, so that answered that question. No more puddle now. If necessary, dig up the dirt & install some 4" PVC pipe. The downspouts would go directly into the PVC, and the plastic pipe drains to some place far away. Looks better but can become plugged with leaves.

The other one isn't practical - how far out do the eaves on your roof extend? Mine extend out nearly two feet so they keep the foundation pretty dry. Mom & dad's place has NO eaves so their sump pump gets a lot of work. This is a problem inherent in the design of the house and is not easily fixable.