You might need to call a repairman, but try these three simple tests first.

Poor-draining dishwasher

First, check the drain-hose connection, drain-hose clamp, solenoid and

power supply. If that doesn't yield results, check the three things listed below.

Check the filter in the dishwasher's tub

You'll find the filter either in the bottom of the tub, surrounding the base of the lower spray arm, or at the back.

Check the drain hose

Disconnect the drain hose (usually it's the one with ridges) from the pump and try to blow through the hose to make sure it's clear.

Test the drain valve

If you have a valve bracket, your dishwasher has a drain valve. To test the valve, push on the valve bracket to make sure it moves freely.