Q Answers · Drain & Plumbing
Air Gap or High Loop: What a Viking Dishwasher Drain Needs Here
Short answer
Both, here. Washington's amended plumbing code sends a household dishwasher's discharge through an air gap fitting, so a high loop alone does not satisfy it; Viking's manuals separately require a loop or a drain connection at a set height. Viking Repair Bothell checks for both on a repair visit — call (206) 202-2799.
Two drain routes side by side: a hose fastened high under the counter, and a hose rising to an air-gap fitting on the sink deck with a second hose down.
- High loop: hose fastened up under the counter before it drops
- Disposer inlet, where the knockout plug has to be out
- Air gap: a fitting at the sink deck that the hose rises to
- Second hose from the air gap down to the disposer or tailpiece
- Loop height is measured from the cabinet floor
What each one does
A high loop is the hose fastened high under the counter before it drops to the drain. An air gap is a fitting on the sink deck: the hose climbs to it and a second hose falls away, with an open break between.
On a DFUD042 the two collide: a deck fitting sits at counter height, above Viking’s 35-inch ceiling for the hose. Code governs the fitting, Viking’s limit the loop — ask your plumber.
Viking’s figures, model by model
- DFUD042: a 20-inch loop or a drain connection at least 20 inches off the floor; nothing above 35 inches; hose no longer than 10 feet.
- VDWU524: a loop at least 28 inches above the cabinet floor and the drain connection; hose no longer than 157 1/2 inches.
On a repair visit
We note whether loop and fitting are there, the hose for kinks, and the disposer plug.
Tell your contractor
- Agree the drain route with the plumber before the countertop and sink are ordered, since a deck fitting needs its own hole beside the faucet.
- Keep the drain hose reachable under the sink, not boxed in behind a false back or a drawer.
When to call
Call when water stays in the tub after a cycle, when the deck fitting spits water onto the counter, or when the sink drain gurgles back toward the dishwasher.
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