What Causes Scum to Be Left in a Dishwasher After It Completes Its Cycles?

Scum

• The scum inside your dishwasher is related to the scum you find inside the showers in your home’s bathrooms. It is soap scum, left behind by the detergent you use to clean your dishes. The scum usually builds up around the rubber seal at a dishwasher’s door and on the floor of the unit. In some cases, it could linger on your dishes. While it can occur at the same time as hard water mineral deposits, the two are not related.

Causes

• The main cause of scum in the dishwasher after the unit completes its cycle is too much detergent. If you overfill the soap container in your dishwasher, it will have a difficult time rinsing away all the soap. Over time, the remnants build up into a thin layer of soap scum. If you do not wash out the interior of your dishwasher, the soap scum can also develop as a result of time rather than anything you are doing wrong.

Solutions

• To get rid of the scum, soak a sponge in distilled white vinegar and wipe down the rubber seal. The vinegar cuts through the scum and deodorizes the interior of the dishwasher. Next, fill a dishwasher-safe plastic cup with vinegar and place it in the top rack of the unit. Run a load with the water as hot as possible. The vinegar will break up the scum so the dishwasher can rinse it away. If your buildup is still there after the unit completes its cycle, purchase citric acid crystals at the grocery store. Fill the dishwasher’s soap receptacle with them and run another empty load.

Considerations

• To keep the scum from coming back, reduce the amount of soap you use each time to run a cycle through your dishwasher. Once a month, run an empty load with either vinegar or citric acid crystals to keep the interior of the unit clean. The cleaner the interior is, the better the dishwasher is able to drain scum in the first place. If you cannot find citric acid crystals in a store, you can use instant lemonade mix instead. It isn’t as strong, so run two loads with it to do the job.