Gravity Sump

[Patrick McCaffery]

I recently inspected a split level home which had a gravity sump. There is no pump, there are two pipes coming in to the sided of the crock and one pipe in the center, where the water seems to drain out. Can anyone explain how this system works.

[Jerry Peck]

Drain tiles drain into the crock, the water drains out the bottom. All by gravity to a lower point of discharge.

You only need a pump when you have to pump uphill, otherwise water flows downhill pretty good on its own. ;)

[Raymond Wand]

Also the sediments that may wash in from the tile are trapped in the bowl and not into the drain.

[Patrick McCaffery]

Thank you gentlemen,
I appreciate your response.

[Stacey Van Houtan]

If this home is on a lot that would not allow the center drain to go to daylight then this is what we call a sub-slab floor drain. That means that the center drain will go to the sewer. This will many times mean that the area the home is in will have a combination storm/sewer. If the storm water overwhelms the system it can back up into the basement, a backwater valve is a suggested upgrade in this sitiuation.
Had a basement last year do this 2 days after closing, i was glad that i had reported the suggested upgrade.