scroll down this page to the table with the various noise sound levels
at:
http://ehp.niehs.nih.gov/members/2005/113-1/focus.html

i was only once was lucky enough to buy a dishwasher that was quieter
than the microwave oven. if the dishwasher shoppers don't hear the
machine running in the store connected to water they won't really be
able to compare it. the machines rated with decibels or sones are very
few, so shop wisely. we have a year old cheaper bosch and it's noisier
at 58db than a ten year old german made ge monogram no longer made
there. there were newer bosch models that were quieter in the $1000
price range than the $500 model by about 10db. the appliance companies
and ownerships and country of origins are always changing.
for appliance repairs also see:
http://fixitnow.com/wp/category/dishwasher-repair/