When a dishwasher discharges its wastewater, it uses a pump to quickly move a lot of water. If anything in the drain line or the garbage disposal impedes the high volume of water, it will back up into the sink through the drain or the garbage disposal. Following regular dishwasher maintenance tips like clearing clogs, keeping them cleared, and occasionally running the disposal will eliminate the problem.

Whether it's worth repairing your garbage disposal depends on its age and the specific problem. Generally, if the unit is eight years old or younger, repair is a good option. For minor issues like a bad seal or a simple jam, a repair can be inexpensive, sometimes under $10. However, if the motor is broken (a repair that can cost $150 or more) or the unit is getting old, it's often more cost-effective to replace the entire disposal.

While the drain connection for a garbage disposal is nearly universal and fits standard sink drain holes of 3 1/2 to 4 inches, the size of the disposal unit itself is not. You must have enough space in the cabinet underneath your sink to accommodate the disposal's housing. A larger model may not fit in a compact cabinet or if the existing plumbing is arranged in an unusual way. Before buying a new garbage disposal, measure the available space under your sink. If you are replacing an old unit, it's often easiest to choose a new model of a similar size.

On average, it takes one to four hours for a professional to install a garbage disposal. This includes removing the old unit, taking necessary measurements for positioning, removing and fitting new pipes, and installing the brand-new disposal system. If there are unforeseen issues, such as accessibility concerns, the process takes longer.