A home with a flooding crawl space has a serious problem. Whether the water is coming from the walls, the floors, the wall/floor joist, or from a plumbing leak, it will lead to damage that will affect the entire home. Rot, mold, sagging floors, and smells are all symptoms of crawl space water. A flooded crawl space will also attract pests and vermin such as mice and termites, which will set up shop in your home for the long haul. Click to read more about crawl space pests.
Simply put: you don't want a flooded crawl space, you don't need it, and you can't get rid of it. Builder Magazine states that 19% of home buyers refuse flat out to live in a fixer upper when shopping for a house- those who are willing to consider the sale will expect a discount to compensate for the problem. This is especially true if the crawl space is causing the floor above to sink or is causing foul odors to seep upwards.
If you're considering selling the home in the future, then fixing the crawl space is the easy solution. Installing a sump pump to remove the water will usually take less than a day. The installation is inexpensive and easy, and it immediately pays for itself through the value of the home, not to mention how much trouble it will alleviate when you try to sell the house.
Fixing a flooding crawl space is easy. If the crawl space has a dirt floor, then a drainage swale can be dug around the edges in the earth, leading any water that enters the space to a sump pump system. The sump pump will then discharge the water, sending it downhill outside of your home.
A good sump pump should be cast-iron (Zoeller is a great brand) and should include a anti-clog sump pump switch and possibly a battery backup pump for power outages, depending on what you use your crawl space for. The system should have an appropriately-sized liner that's neither too large nor too small, and it should rest in the stand on a sump pump stand that will prevent debris on the bottom of the liner from clogging the system. To help guard against sump pump failure, it's important to install an alarm that will sound off if the pump is not working. Additionally, be sure to have a serviceman perform annual maintenance on the system to ensure proper function.
The best reasons to stop crawl space flooding are to prevent mold and to recover the crawl space as usable storage space. However, a sump pump alone will not be able to accomplish this. To really keep the space dry, it's best to encapsulate the crawl space by installing a vapor barrier, crawl space vent covers, an airtight crawl space door, and possibly a dehumidifier. Click to read about crawl space encapsulation!