Defective Supply Hose
The water supply hoses located in the back of the washer deliver water to the machine and are prone to leaks. Test the integrity of the supply hoses by draining the washing machine of water, moving it from the wall, so the hoses are visible and turning it on.
Once the machine begins filling with water, examine each hose, both cold and hot water, for signs of seepage. After the leak is identified, replace the faulty hose with a new one from a hardware store.
In some cases, it's not a hose that's defective, but its washer. The washer serves as a seal that prevents water from leaking at the point where the hose attaches to the machine.
The seal can break over time with repeated use. Switch out the failing washer with a new one when the leak appears confined to just the seal.
Leaky Water Pump
If water isn't leaking from the back of the washing machine, open up the washer's main access panel. Consult your washing machine guide for assistance.
Locate the water pump. If you spot water dripping from the water pump near the bottom of the washer when the machine is on, the seal around the pump is likely shot.
An entirely new water pump is needed to stop the leak. Contact a repair technician if you're not comfortable making the repair on your own.
It's not a difficult part to replace, but it requires some general knowledge of washing machines to complete the task successfully.
Obstructed Floor Drain
A water pump removes water from a wash tub through a drain hose that transfers it to a floor drain. If the floor drain becomes blocked with residue or debris, water can overflow the drain and end up on your laundry room floor.
Locate the floor drain near your washing machine. Inspect it to make sure that water hasn't collected inside, and that it is able to drain properly.
Flush the drain with clean water using a garden hose to clear out suspected blockages.