Water drainage systems allow you to comfortably use the space under a high deck.  These systems divert water away from the underside of your deck to create a dry space with an attractive ceiling.  You can essentially double the outdoor living area for an affordable price.  These areas can be easily converted into screen porches by adding walls. 

Water drainage systems installation varies by manufacturer.  Some systems are composed of waterproof sheets installed under the deck between joists.  Other systems are attached to the top of the deck frame and under the decking.  Always consider the method of installation when researching water drainage systems.