Air gaps are ugly and useless nanny-state intrusions on countertops. Bring the dishwasher drain hose through the top of the sink base cabinet and forget it. The same California morons requiring air gaps are also giving the state shutdowns and the highest rates of Coronavirus spread. Apparently things that work great in the other 49 states are lost on these people.

Thanks. When the water came back on, we now have a problem with our upstairs bathtub faucet. It will not turn off. It is not running full blast, but it is running a steady stream of water. It is now 15 days later, and we still have not had a plumber return our calls. We have called 27 listed as local plumbers within an hour from us. Many have gone to Texas to make more money. So, my water bill is going to be huge next month. What do we do? There is an acrylic shower surround/tub that we didn't plan on replacing. The faucet is a Delta, and it could be anywhere from 15 to 25 years old. Probably the same age as the valve. Lowes people said it can be rebuilt, but we always hire plumbers. Since we can't find a plumber, what do we do? Thanks.

I think you are asking about the expansion plug used in place of a threaded clean-out plug. Odors can drive one nuts when they have eyes and nose on site,I don't even attempt locating them from 1k miles away. Water heaters often impart a sulfur odor to water. This isn't the silver bullet you were expecting but here's a test. Double bag a 20-30 gallon trash can with over-size plastic bags. Sit can on stool.blocks or other support tall enough to allow tapeing bag opening over shower head. Run shower the minimum time it normally take's for odor to be detected. If no odor is detected,,,,,,,,until bag is opened you've found the source. If no odor before or after opening bag,empty can into drain to see if odor is then detected. Report back with results and we can talk about remedies.

Had the exact same scenario at my sister's condo. While it is possible to have a crossover through the shower valve, I was sceptical. I refused to use their unlicensed "plumber", and the HOA can't force you to use their plumber. We reached an agreement with the HOA that our licensed plumber would replace the cartridge in our bath. If that fixed the problem for the other units we would pay for the repair, and if it did not fix the problem the HOA would pay the bill.