If you see water dribbling into the basement through cracks or gaps around plumbing pipes, you can plug the openings yourself with hydraulic cement or polyurethane caulk for less than $20.

Plugs work when the problem is simply a hole that water oozes through, either from surface runoff or from wet soil. But if the water is coming up through the floor, or at the joint where floor and walls meet, the problem is groundwater, and plugs won’t do the trick.