My house is 24 years old. It is built on a hillside with a walkout basement.
When I bought it 12 years ago I found the sump pump was installed incorrectly and couldn't work. I fixed it and it worked fine when I flooded the sump. It has never actually cycled because of water in the sump.
A few months ago we really heavy rains and snow melt; there was flooding all around. The bottom of my sump had an inch of water in it, but it would have to come up about 16" to cycle the pump. When I emptied my water heater into it, it emptied immediately. So, you get the idea that I am pretty dry.
Okay, the problem. Just for the heck of it, I tested the pump today. It doesn't work.
I drain my shop sink into the sump, but could still do that; I don't use it much.