We didn't notice when we bought the house that the entire back yard slopes toward the house. Nor that several of the neighbors' yards are higher than ours. The result is that during a heavy rainstorm, like the one last night, the neighborhood's water wants to get into our foundation.
We did know before buying that we'd have to have the foundation repaired sooner or later, so we went ahead and had it done last fall (left). That caused any water that does get into the foundation to go into the sump pump hole (right) where, given electricity, the sump pump will get it out of the house. So far we haven't lost power, so that's been OK. But when the foundation crew was done filling in the trench, they just left the extra subsoil where they'd put it. They didn't sculpt it to divert water away from the house -- that wasn't their job!
The first time we got a heavy rain this spring, I was surprised to see water coming in the opposite wall that we hadn't had repaired, the wall that has a solid expanse of concrete (the driveway) outside it. Well, not totally solid. When I went out to take a look, I saw a stream of water coming from the back yard and disappearing down one of the driveway cracks! So I caulked that, and it's been much better since. But where was all the water coming from? It was dammed up by the piles of subsoil in the back yard.
Fortunately I talked to a neighbor about it, and he said he'd helped a previous owner dig a trench to keep the neighbors' water out of the yard, but that the extra soil (not from the foundation repair, from the earlier sewer repair) had been piled on top of the drainage trench. So we excavated that, and that helped.
I've been gradually moving more of the soil to make a dam that diverts what water does get into our yard onto the newly patched driveway, where it can get away ASAP. But last night I found that, since the dam isn't at its full size yet, it was creating a pool that then sunk into the trench from the plumbing repair and (surprise!) created a small fountain in the back wall of the basement. So clearly we need to get water away from the foundation more quickly!
In the long run, we hope and plan to turn all the extra water into an asset instead of a liability. Rain barrels (with overflows) on the drain pipes will let us use some of the water later. Small ponds will keep some of the water in the ground without letting it into the foundation, so we can experiment with wetland plants and fish and all the other good things ponds can provide. But for now it's a small crisis every time there's rain in the forecast!