This will help you decide if you want to make the investment. This will give you enough room to fit the base of the pump and the discharge pipe. Crawl Space Sump Pump Installation Cost: Installing a sump pump in a crawl space can be a tricky undertaking. You need to know the difference before purchasing a sump pump. Water damage can cause toxic mold growth, which can result in expensive repairs. Use a hole saw with a bit sized appropriately. This is especially helpful if you have an unfinished basement. This is especially useful if you have a crawl space or a basement. When the float switch is activated, the pump should turn on to drain the pit. For a standard pump, you can expect to pay around $ to $.