Thanks for your kind words about The Money Pit! To answer your question: I think you may have misheard me. The type of soil needed is "clean fill dirt" - not "filtered." Any landscape supply outfit will understand what clean fill dirt is - and it's a great tool for keeping water out of your basement. Make sure the clean fill dirt is free of debris, and grade around your foundation's perimeter so that it drops six inches over the first four feet. As another line of defense, add topsoil and grass seed, or another covering that's more organic, once that grade is established. The key here is, don't built the slope with topsoil - a common mistake. Topsoil holds water against a house like a sponge, only increasing the chances of moisture inside.