- Q.A client wants to locate
her dishwasher in a peninsula several cabinets away
from the kitchen sink. Are there any limitations on the
distance that the discharge hose can travel, or should
it be plumbed separately?
A.Mike Casey, a licensed
plumbing contractor and co-author of Code Check
Plumbing, responds: Most dishwashers come from
the factory with a 6-foot 6-inch drain hose, and
nearly all manufacturers allow this hose to be
extended to a maximum total length of between 10
and 12 feet. A heat- and detergent-resistant
7/8-inch inside-diameter extension hose can be
connected to the existing hose with a section of
3/4-inch inside-diameter copper tube. During
installation, try to keep the number of bends low
and the run as short as possible, since a lot of
bends and a long run will increase the load on the
dishwasher waste pump.
Dishwasher hoses should have a high loop at
least 20 inches above the finished floor to prevent
wastewater from entering the appliance if the drain
clogs. Code requires that the hose connect to the
sink drain on the sink side of the trap, typically
with a branch tailpiece.
Some jurisdictions require an air-gap device, in
which case the hose should connect to this device
first, then terminate at the branch tailpiece or
garbage disposal.