Smelly Soda Machine and Ice Well Drains in Restaurants

The complaint is nearly always the same: customers and staff notice a sour, sewer-like smell near the soda fountain or the bar ice well. Staff have already poured bleach down the drain and changed the machine's filter, and the smell is back within a day or two. Nothing is leaking and the drain still empties, which is why it gets ignored for so long.

The usual cause is simple. Syrup, sugar and ice-melt carry food for bacteria, and the drain line from a fountain or ice bin is often a long, nearly flat run into a floor sink. A slime layer builds up inside it. Where the floor sink has a trap that dries out between uses, sewer gas comes up as well.

We start by finding which of three things is making the smell. We pour water in the floor sink and watch whether the trap holds. We check that the equipment drain ends in a real air gap above the floor sink, not a pipe pushed down into it. Then we run a camera or a probe into the line to see how much buildup there is and whether the pipe sags.

An air gap matters here. Plumbing rules treat equipment that holds food or ice as indirect waste, so the drain must discharge above the receptor with a visible gap, which stops sewage from backing up into the ice.

Bleach on top of the drain doesn't reach the pipe wall. What works is a combination of steps:

• Jet the line with a cleaning solution from the floor sink through the run, so the slime layer is scoured off the pipe wall instead of pushed along.
• Restore the trap seal by running water or adding a trap primer so the floor sink does not dry out.
• Fix the air gap if the equipment drain is submerged or pushed into the receptor.
• Correct the slope if a sagging section holds standing water. That is the one that comes back unless the pipe is reworked.

Jetting runs one to two hours, and it can be done before opening or after close so the kitchen isn't disrupted.

Tell us which drains smell and whether it's worst after a slow stretch, like a Monday morning, because that points to a dry trap. Don't pour drain chemicals down a line you plan to have jetted, since the cleaning solution can react and the product can splash on the person working. Ask the person who services your ice machine to confirm that the machine itself has been cleaned, so we are not chasing a smell that comes from the bin and not the drain.