What if you have water under your house?

Your land drain might be cracked

Could be ground water after a rain. Sometimes it may take days for ground water to percolate to the surface. Your crawl space may in a low ground area.

Be sure the ground around your house is graded properly so rain drains away from your house.

If you have no leaks, you could have a drainage problem and need to put some kind of a drainage system around your house. You don't want mold and rot growing under there. It is a health hazard. There are french drains that can be put around the foundation of the house that can drain the water away. It amounts to digging a trench around the foundation, laying gravel in the bottom of the trench, and putting a corrugated pipe put down in the bottom of the trench that can carry the water away from your house. I believe the pipe will have holes punched in the top for water to run into every few feet to catch the water that would normally be running under your house. While you have the trench dug, you should seal the foundation with some kind of weather sealer, too.

Make sure your gutters and downspouts are cleaned twice a year, and that the downspouts have extensions on them to drain water away from the house. You can also add splash guards under the downspouts to prevent pooling around house. I also make sure all debri is well raked away from foundation.

Put a sump pump under there too