Although interior water drainage is not technically waterproofing , it is a widely accepted technique in mitigating basement water and is generally referred to as a basement waterproofing solution.There are a number of situations that may determine if an interior drainage system is the solution best suited to your particular needs . Firstly , if your leak is caused by hydrostatic pressure forcing water up from under the basement floor slab , no amount of digging on the outside will solve the problem , you must install an inside drainage system to control this water . There are situations where the leaks are coming through the foundation but an exterior repair is impractical or impossible due to obstructions or elaborate landscapes . Lastly if budget is a concern an interior drainage system is generally 40-50% cheaper than an exterior repair .