I have a 12 yr old home with a plastic sump liner installed, but no pump. The sump filled 2 yrs ago and I used a portable pump with a float switch to empty it. I left the pump in and it runs a couple of times a year. I wish to install a permanent pump prior to radon remediation. There is one 4 in tile which enters the liner at about the median point. There is 3 in of water in the sump. There are no other perforations in the liner. It looks like water enters from around the 4" tile. Do I need to perforate the liner to allow water (and air for radon) to enter freely?
It's not uncommon for the water to enter below the 4" tile, as it's likely well-perculating stone around the pipe & crock, and the holes aren't an exact fit to the pipe as they don't need to be. As a general rule, I don't like ot see water any higher than at least 8" below the floor. More is better. It sounds like you're stays far below that, which is great.