If your dishwasher isn’t draining, some common causes include a clogged drain filter, drain hose, or air gap. Also, if you have a garbage disposal, a clog in the disposal can back up your dishwasher since they share plumbing, as can a clog in your kitchen sink’s plumbing. A handy DIYer may be able to figure out how to unclog a dishwasher, but you may need to call in a plumber if you can’t locate and clear the clog yourself.

To create a siphon break and remove any chance of dirty sink water or water that backs up into the sink from getting into your dishwasher, your dishwasher drain hose needs to have a high loop or an air gap device as part of its installation. All building codes require at least a high loop. In many places, it’s necessary to install an air gap device to meet the code.

Not all dishwasher noises are signs of trouble, as dishwashers naturally make sounds during operation. Normal sounds for a functional dishwasher include humming, swishing, and sloshing. However, if you hear problematic noises such as pounding, drumming, grinding, or rattling, it could be a sign of an underlying issue, and you should consider having a technician inspect your appliance.

When deciding whether to repair or replace your dishwasher, consider its age, the repair cost, and its warranty status. It is often worth repairing a dishwasher if it is only a few years old, the problem is minor, or the appliance is still under warranty. A common guideline is the 50% rule: if the repair cost is less than 50% of the price of a new unit, a repair is generally recommended. However, if the dishwasher is more than 10 years old or requires frequent repairs, replacement is likely the more cost-effective choice to avoid future issues. For context, a new dishwasher costs between $1,000 and $1,500 on average, while typical repairs cost several hundred dollars. Simple fixes like a damaged gasket or clogged filter can be inexpensive, but major repairs like a new pump or motor can be costly.