Rental properties are big in certain areas. With the economy crash more people are starting to rent properties because they do not have the means to purchase. This is not a bad thing because the needs for rental properties have increased owners are pleased with the results. Rental property owners have a lot of responsibility with the up keep of their properties. Although the owners can hire outside contractors to help with most of the up keep like; pluming, lawn and yard treatments and anything that breaks inside the home. The owner still has a lot on their plate.
The property itself has to be kept up according to state property laws in the area where the property is located. The structure of the property itself has to be maintained so that renters can continue living in the property. It is the owner's responsibility to fix and thing that breaks in their properties they rent unless stated in their rental agreement. This is probably the second reason people chose to rent. With the economy being so bad they do not have the fund to fix a broken pipe or water heater. When you rent from the right owner this is not a responsibility of the renter.
Now there are laws that property owners have to abide by but some of them do slip through the cracks and get away with being what you would call a slim load. A slum load will let problems go until they affect something else in the property and then you have a big mess. These types of owners are still around because they normally do not get reported. There are laws that will protect the renters from landlords like these.