Increasing depth of sump bump basin

Hi,
Recently a plumber doing work at my house mentioned that my sump pump basin is too shallow in relation to the drain pipe height in the basin. The drain enters the basin at about 2" from the bottom.

For the pump to turn on, the basin has to fill up to the top of the drain pipe, meaning that my drain tube is always almost full and is keeping the wall footing in water. The pump stops when the water is at about the bottom of the drain.

I have a Liberty Pump 257 with a built-in float and I can't change the float start/stop height. Also the pump stops when the water lever is at the bottom of the drain pipe, not below the drain.



It's an old home that we had the basement excavated 10 years ago and there's a drain on the inside of the foundation. The drain goes around the perimeter and ends in the basin. The basement has a concrete floor and the basin is encased in the floor.

The drain is 18"x25" and 18" deep.

The fix:
I could break the concrete and install a deeper basin and it's a lot of work but before I try, I thought I could try to extend the depth of the basin.

I want to cut the bottom of the basin, dig the bottom, add rocks and insert the bottom half of the same basin model. I know the fit won't be perfect because of the trapezoidal shape of the basin but I could look ok and I could cut some relief in the side to make it fit better.

The problem with this approach might be that surrounding water could enter through the joint that the new minimum water table height would be at the joint and my pump couple potentially have to pump more water.

What do you think about it? Maybe it's not worth doing or there's a 3rd option.

Thanks

 

Do not worry about water entering the sump from other than the pipe. It's OK. The bad part is water entering from elsewhere can wash the soil away so you do want to put some stone around your new, deeper sump if you can.

To get benefit from deepening your sump you will need to change the float switch. You need a switch that will allow you to take advantage of the extra sump depth so the pump can run for a longer period of time when it does run. Putting your pump in the bottom of your deeper sump will help still help since all the water will be kept at a lower level. You just won't be able to take advantage of the greater tidal volume to reduce how frequently the pump cycles on and off.

 

So your situation is exactly the same that I have fixed in several homes. The sump doesn't need to be deeper, you just need to raise the pump upward so that more water collects throughout the sump tiles so that when the pump runs it's removing a greater amount of water.

Lowering the sump pit will only add a few gallons, raising the pump will add hundreds of gallons and keep that pump from short cycling constantly when the influx of water is great.

 

If I raise the pump, the drain will be mostly full, isn't that a problem?

Thanks

 

It's already full of water, that is what it's intended to do!

 

The pump should start no later than when the water has risen to fill more than 2/3 of the drain pipe. There must be an air pocket in the drain system all the way around the basement perimeter. Otherwise the far corner of the basement could flood when the sump pump appears to be working normally.

If you can prove that the perimeter drain pipe is higher than its round opening into the pit (and has an extra slope down on its final approach to the pit) then you can let the water in the pit go higher than 2/3 of the height of the round opening before the pump starts..

Ideally, once the pump starts it should keep going until the pit is nearly empty. If during some times of the year the water level in the pit levels off or stops rising before covering the drain pipe opening 2/3 then it can sit that way indefinitely without the pump running.