A dishwasher can back up into your garbage disposal, potentially causing damage. Here’s how to make sure that doesn’t happen.
For the most part, dishwashers and garbage disposals are built in such a way that they don’t interfere with each other. The units are usually installed in separate areas under the kitchen sink—one on top of the other—so they won’t be in danger of backing up into one another. Sometimes, though, when an inexperienced plumber or homeowner installs them incorrectly, one appliance may end up partially blocking access to the drain opening where the other is supposed to go. If this happens, it could cause either appliance to back up into the other one.
The most likely cause of a dishwasher backing up into a garbage disposal is improper installation, but there are some other possibilities, too. If you have the bad luck to live in an area with rock-hard water, for example, bits of mineral buildup inside your plumbing system could create narrow spots that slow down the flow and give solids time to settle out. These clogging deposits can be mistaken for long hairs when viewed under magnification—hence the old wives’ tale about tiny ringlets getting caught around moving drainpipes in sinks and tubs.
It’s also possible for foreign objects—such as toys or plastic silverware—to find their way into your garbage disposal or washer and get stuck somewhere along the way. This can cause either appliance to back up, though it’s more likely that the dishwasher would drain slowly or not at all without flooding your kitchen.
Remember, if you suspect your dishwasher or garbage disposal is backing up into the other unit, the best course of action is often simply to shut off both appliances and get in touch with a qualified plumber. An expert can inspect both appliances and determine which one is causing problems for the other before doing any corrective work.
A garbage disposal back up into a dishwasher occurs when something blocks access to where one machine drains into another, preventing waste from exiting properly. Improperly installed appliances are common culprits, but foreign objects like toys or plastic silverware can also get stuck inside either appliance. Shut off both appliances and call a plumber if you suspect a backup has occurred.