Do you mean water leaks from top or bottom of machine, or is water coming up through the drain in the floor, making the floor wet? If it one of the first two, then there is a problem with the machine and the landlord should get it repaired. They do have a filter on the back somewhere on the hoses which may need to be cleaned or the hoses may not be tight enough. If water is coming up the drain in the floor this means too much detergent is being put into the load. The following tips on correct use of top loaders may help with cleaning and clothes care.
Place clothes in first, loosely with each item bunched, not wrapped around the washer. Do not keep stuffing them in by pushing down, this overloads the machine and they can't move freely to wash and won't clean or rinse well. The machine is full when the clothes naturally reach just below the top, with no pushing in.
Add a small amount of top loader detergent. You can get away with less than the recommended amount for lightly soiled clothes. If water and suds come up the drain, use less detergent next time. Towels require only about 1/3 of the recommended amount. You will learn how much is needed and save money on detergent.
Set the water level according to how many clothes you have in the machine as others have suggested.
Start the wash..........then add that odd sock you find on the bedroom floor (the great advantage of top loaders)
The clothes should be clean and the floor dry. If not review detergent use, check hoses and filters and if these are all OK, get it repaired or replaced. If the Landlord isn't helpful, this link may be useful