I have the typical Sump Pump setup with a 1HP pump and what seems to be drainage tile leading into the basin. Works fine 99% of the time but in a very big and long storm the pump isn't enough and the basin overflows into the basement. What I don't understand is why this kind of setup has to be an "open system", meaning it may overflows. Why can't we have a "closed shut" system, like in an ejector pump? So in case of excess pressure, the water would be just pushed along the pipes to outside the house instead of flooding my basement? Ideas? Thanks
You'd stop the flow for a while, then it would come up through all the joints and cracks and gaps in the system. (A home's foundation and floor are not really like a swimming pool. They're not intended to be water-tight. Very little pressure would be present.)
What you'd be left with is essentially a home without a drainage system, subject to all the flooding and related unpleasantness of centuries past.
Hydrostatic pressure can do serious damage. The basement floor would likely buckle first, before it raised (floated) your entire house.
Depending on how often this happens you should either get a pump with a higher GPH flow rate, or add a second auxiliary pump.
Related: Check these swimming pools that floated out of the ground as a result of hydrostatic pressure.