My basement has flooded twice over the last couple of years because of power failures. I am thinking of putting a cover over the basin to keep the water from coming in. Will this cause any damage to anything else when the water backs up? Keep in mind that it would only be for less than 12 hours (most likely less than 3).

 

Covers don't prevent your sump pump from overflowing... they prevent you from stepping in the hole. You need a backup sump pump. They are available with battery power, or you can get ones that work off your city water pressure. (No battery to replace and virtually endless operation in the event your power is off for more than a few hours... even a battery backup will only provide you a few hours worth of operation during a power outage.)

 

But what if it was completely airtight sealed?

I am also thinking about having a solar backup, but was also wondering about what would happen if it was sealed.

 

You can't pump the water out of the sump if it's airtight. It will create a vacuum and stop the pump.

Also, if you completely seal the lid the water will go somewhere else. That's why you have a drainage system and sump in the first place. It's the path of least resistance to make the water go that way. If you seal the lid the water will just bubble up somewhere else in your basement.

You have to pump the water out... period! If you don't pump the water out it will end up in your basement somewhere.

 

I would suggest a small generator to use in the event of a power outage. I've seen all types of battery back-ups, jet pumps, etc... Most fail at the most impromptu time.
The most reliable is the generator.

Just a note. The jet pump does work. However, keep in mind that you are just pumping or adding additional water out that will be coming back in.

 

Why wouldn't a one way valve on the sump pump cover work?

It would let air in one direction (no vacuum) but still seal the water from coming out.

 

How wold you propose to add a sealed cover on a sump pit?
Besides if for whatever reason a pump fails and the pit fills, it has a lot more pressure than you realize and would most likely break any seal you make. And as mentioned earlier if you were able to prevent the water from rising into t he basement, it would look for the next weakest point. And that could be your floor. Or walls! If you have valuable material in your basement you have two options. 1) remove it from the basement. 2) put it up on bricks. But any flood that can rise above bricks over the full volume of the basement is major and you won't prevent or save anything.

 

Your basement is not waterproof. The sump system keeps the basement dry by pumping away water faster than it's coming in. If you seal the sump the water will rise underneath your basement and find other ways in. Likely through cracks and expansion joints in the floor and where the floor meet the walls.

Sealing the lid of the sump isn't going to keep the water out. You need to make sure the pumps keep running.