Dan,

And then there are those 'spensive foreign D/W's that have a checkvalve built into the drain mechanism on the unit.

I've run into a few of those units when I was doing some extremely 'high-end' new home finals while I was inspecting in the Houston market.

Many of these D/W's started at about $3K to $4K and on up from there.

__________________
Cheers - Nolan E. Kienitz, HCRI, PMP
ICC Certified Residential Plumbing Inspector (P-1)
www.NolansInspections.com