Turn off power to the dishwasher before you attempt to do anything else.

These are the large arms that rotate inside your dishwasher and spray water onto your dishes and utensils. Check that they can freely rotate. If you have oversized crockery in your dishwasher or long utensils, they might be blocking the spray arms from rotating, causing water to be sprayed at the dishwasher door seal, with resulting leaks.

You can remove the spray arms and check that there are no blockages which might cause them to operate incorrectly. You can use a needle or similar to clean out the water slots. Even a new spray arm is usually very affordable.

The seal/gasket which goes around the door and along the top of the door is easy to remove or repair. Check that it isn't perished or badly fitted. A new seal can be purchased and fitted if necessary. The task of removing and replacing this seal is fairly straightforward.

The lower seal that runs along the base of the door often requires removing the door. Since this is a more difficult procedure, you may prefer to engage the services of a professional engineer to accomplish this.

Common causes of leaks also include the drain pipe being cracked or loose, so check that the leak is actually originating from the inside of the washing vessel. If it isn't, check the water connections (inlet and outlet (waste). It might look as if the water is coming from elsewhere but it could be coming from a leaky pipe and pooling on the floor.

At the bottom of the dishwasher tub, there is a water inlet valve which is designed to control the volume of water which enters the dishwasher. It uses a float valve to detect the amount of water in the dishwasher and if it malfunctions, can cause your dishwasher to overfill with water, which may leak our from around the vessel seals/gaskets. These parts are harder to repair and if it is the valve itself, will probably need replacing.