Trusted Websites
BBB Member- No complaints
Good source for Crawl Space vapor barriers and info on crawl space insulation Take a look at their blog, good stuff there too
A site designed to teach step by step how to create a conditioned crawl space.
A research firm that has done extensive studies on crawl spaces
Good resource on dealing with Mold in a crawl space.
A great article on controlling the crawl space environment.


Crawl space fungus 

Water in the Crawl Space is

Bad News....

Before you pay someone to install a sump pump in your crawl space, consider what really needs to be fixed. Keeping the water out in the first place is a much better plan, not to mention that it saves your foundation from taking a dip every time it rains. Crawl space water problems have to be fixed before you have any chance of controlling the moisture. Here is a good article on crawl space moisture and the effects it has on your home.
Downspout causing water problems
Not much to figure out here, downspouts can deliver up to 6 times more water than a garden hose.
All downspouts should have at least 4-5' extensions to get the water away from the house.

Diverting roof water away from the home 
Bury the Downspouts
The best option for water control is to direct the water away from the home underground. This method will relieve a lot of water from around the home.
Use a flexible drain pipe with a soil sock to prevent the pipe from getting clogged with dirt.

Negative grade slopes toward the home
bad grade
Always have the grade running away from the house. When the ground slopes toward the home, water sits against the foundation causing leaks.
Never use mulch or rock to correct the grade.

Sump Pumps can keep the crawl space dry
Sump Basin
Once the water problems have been addressed outside you may still need a sump pump to discharge any remaining water. Standard basin size 18" x 22"deep.
The size of the basin is very important. Small or mini basins will shorten the life of the pump by causing it to short cycle.