A leaky dishwasher is easy to detect, but may not be as simple to diagnose or repair.
If you're lucky, the dishwasher leaking may be temporary. Caused by overloaded or clogged dishwashers, a temporary leak can be easily fixed. You can troubleshoot your leak by cleaning out the traps, making sure (if applicable) the garbage disposal and/or food chopper is clear and running an empty load.
If the dishwasher still leaks after you've performed these troubleshooting steps, you may need to make a repair. Your first step is to shut off the electricity to the dishwasher. You can do this by shutting off the breaker to that area of your kitchen or by removing the dishwasher from under the counter and unplugging it.
Next, check your door gasket. Gaskets and seals can harden and crack over time. If the door gasket's seal is broken, this could be the source of your leak. The door gasket can be taken off and replaced without any tools. However, another gasket can cause the tub to leak: the soap door gasket. If this is the case, you will need to remove the screws from the front panel to reach the gasket.
Another leak possibility is in the discharge gasket. That gasket is located under the lower spray arm, which will need to be removed to access the gasket.
If none of these gaskets are the root of your leak, you may have one of a variety of issues: hose leaks, pump and inlet valve leaks, damaged spray arms or a broken float switch.
For hoses, check connectors and clamps. Tighten or refit these weak points in the hose assembly. If this is ineffective, you may need to replace a leaking hose.
The pump and inlet valve work together to get water in and out of the dishwasher tub. The inlet valve itself does not often leak, yet the water supply it connects to may leak. It may also stick open, allowing water to flow freely. Stuck valves and leaking around the valve requires replacement, while pump leaks may be repairable through replacement of the pump seal (this is the case only if the pump body is uncracked). Note: if you have a horizontally mounted motor, the pump isn't serviceable and the pump and motor assembly will require replacement.
Broken spray arms can misdirect water and cause the tub to leak, requiring replacement of the arms. A broken float switch necessitates replacement or the water tub will continue to fill beyond the tub's capacity.
If water is leaking not onto the floor but onto the countertop or even into the sink when the dishwasher runs, you may have a problem with the dishwasher's air gap. If you have a new garbage disposal, check to see if the knock-out plug has been removed. If not, your washer will not drain properly. If the plug has already been removed, you'll want to check the hose to the disposal for leaks.
Why should you repair or replace even minor dishwasher leaks?
Even minor dishwasher leaks can cause serious damage over time. Between rotting floorboards and mold issues, leaking plumbing of any variety should be repaired by yourself or a licensed plumber immediately.
Mold in the flooring or cabinets can be a serious issue that needs to be part of repair of your dishwasher repair if the leak has been ongoing or undiscovered for some time. With any leak, you should check for wood damage as a matter of course because leaks could have been undetected for a time. Particularly in the humid climate of Atlanta, mold can grow quickly.
In order to check beneath the dishwasher and behind the cabinets for mold, either call a licensed mold remediation company or perform a few checks yourself. Your first step is to check if any of your cabinets are easily removable or a board can be pulled off without drilling.
If this is the case, remove the board or cabinet and check for black mold. If not, you'll need to saw or drill through part of the cabinet baseboard and check for mold.
At this point, if you find mold, you'll either need to clean it or remove and replace any wood or other materials on which the mold is growing.
If you have a dishwasher leaking and need to clean up after the water, you'll need to clean and dry any damp materials within 24-48 hours to prevent the mold from growing. You also need to clean the mold off any hard surface with water and detergent.
Any absorbent materials will likely need to be replaced rather than cleaned. For more information on mold, check the EPA's mold resources page.