david wrote:
If I want a drainage system in my dirt crawl space, is french drain the only
choice? I believe they clog up after a number of years, perhaps between 10
to 20 years.

I need a non clogging drainage system because I also want to install a vapor
barrier that seals the ground as well as the foundation wall. If the
drainage system clogs, I would have to rip the vapor barrier to repair it.

I'm located in washington state near seattle in case you have region
specific recommendations.

I can't imagine putting a french drain under the house. It is for
*grey* water? Grey water drains not allowed there and don't want anyone
to see it?