But during moderate to heavy rains or when snow begins to rapidly melt water can oversaturate the soil surrounding your basement walls to the point where it eventually seeps through the foundation and onto your basement floor. Apart from rain sources of water leaks include roof spillage surface runoff improper exterior foundation drains and clogged gutters and downspouts. French Drain System For A Foundation Drainage To Prevent Water From Leaking Into A Homes Basement Foundation Drainage Backyard Drainage Yard Drainage This usually happens after a heavy rain andor when snow melts rapidly. Leak in wall when it rains . The first is to determine exactly where the leaks are coming from and what might be influencing the amount of water sloping against your house. Check under sinks first but if a drainpipe is leaking from a connection in a wall you have to remove some drywall to find it. The foundation walls surrounding your basement are designed to keep water and all other elements out ...