I have a 60 year old house with a basement that has always had a sump basin and pump. This year I have been working to finish the basement with a 3/4 bath and have the shower drain area nearly ready to concrete around the p-trap (there is a 2'x2' square cut out in the basement floor with exposed sand/fill. My house sits at the bottom of the hill and the water table is never very far below the slab floor, perhaps a 18 inches in the winter. The pump keeps the water in the basin at 12 inches below the basement floor.
This year has been an extremely wet summer, with almost all of the year's rainfall coming since mid July and the water table has come way up, in fact to above basement floor level. I have done quite a bit of vacuuming and mopping of water coming up through cracks in the floor and especially where the slab meets the foundation. Basically the basement is a hull that is taking on water. If the basement was divided into thirds the sump would be in one third of the floor area. Water intrusion got so extreme at one point in a portion of the basement that I dug another sump basin and plumbed another pump...what a treat that was. The new basin fills much faster than the original, that is, when pumped dry water literally shoots through the holes to fill it. Today it is pumping every 12 minutes. The old basin pump which is set at the same level pumps about every 20 minutes, maybe a little slower. Its basin's water holes only weep water. The holes are big enough that I can stick a long thin screwdriver into them and into the sand behind; there does not seem to be any screening or fabric on the outside of the original basin, only very wet sand. The house sits on nice sand, it is in the yard, under the slab where the new basin is installed and everywhere I trenched to install all the new under-slab bathroom drain pipes, presumably around the old basin as well as these new pipes run within a few feet of the old basin.
Ok, here is my question: Can the soil around a sump basin "wear out" over time, that is, could the sand immediately surrounding the old basin become impacted with finer sediments that migrated over the years from elsewhere and decrease the permeability enough to slow the flow of water into the basin? I mentioned my open slab area for the future shower: it is about 10 feet from the original sump and the water level where the concrete is removed is completely up to the top of the slab (draining down the open shower drain, thankfully) yet the nearby (old) basin water level is always more than 12 inches lower. It is like there isn't even a sump in the area at all. The new sump basin has a great effect: before I installed it water was spurting up through cracks 20 feet away, now they are bone dry. I don't want to replace the old basin but if it is possible that the several inches of sand surrounding it could be prone to losing permeability over the decades I would be motivated to break open the concrete, pull it out and replace the surrounding sand with pea gravel to match the work I did for the new basin. My mind is obviously working overtime to find a rational explanation here, maybe my theory is ridiculous. It has been a difficult summer, to say the least. If anyone has any experience or thoughts to share I would appreciate it.
This year has been an extremely wet summer, with almost all of the year's rainfall coming since mid July and the water table has come way up, in fact to above basement floor level. I have done quite a bit of vacuuming and mopping of water coming up through cracks in the floor and especially where the slab meets the foundation. Basically the basement is a hull that is taking on water. If the basement was divided into thirds the sump would be in one third of the floor area. Water intrusion got so extreme at one point in a portion of the basement that I dug another sump basin and plumbed another pump...what a treat that was. The new basin fills much faster than the original, that is, when pumped dry water literally shoots through the holes to fill it. Today it is pumping every 12 minutes. The old basin pump which is set at the same level pumps about every 20 minutes, maybe a little slower. Its basin's water holes only weep water. The holes are big enough that I can stick a long thin screwdriver into them and into the sand behind; there does not seem to be any screening or fabric on the outside of the original basin, only very wet sand. The house sits on nice sand, it is in the yard, under the slab where the new basin is installed and everywhere I trenched to install all the new under-slab bathroom drain pipes, presumably around the old basin as well as these new pipes run within a few feet of the old basin.
Ok, here is my question: Can the soil around a sump basin "wear out" over time, that is, could the sand immediately surrounding the old basin become impacted with finer sediments that migrated over the years from elsewhere and decrease the permeability enough to slow the flow of water into the basin? I mentioned my open slab area for the future shower: it is about 10 feet from the original sump and the water level where the concrete is removed is completely up to the top of the slab (draining down the open shower drain, thankfully) yet the nearby (old) basin water level is always more than 12 inches lower. It is like there isn't even a sump in the area at all. The new sump basin has a great effect: before I installed it water was spurting up through cracks 20 feet away, now they are bone dry. I don't want to replace the old basin but if it is possible that the several inches of sand surrounding it could be prone to losing permeability over the decades I would be motivated to break open the concrete, pull it out and replace the surrounding sand with pea gravel to match the work I did for the new basin. My mind is obviously working overtime to find a rational explanation here, maybe my theory is ridiculous. It has been a difficult summer, to say the least. If anyone has any experience or thoughts to share I would appreciate it.