One of the most important things I have learned being a landlord is that you must be familiar with all laws and rules (Federal laws, State laws/rules, and local ordinances) that deal with a rental operation. In my location for example, at the State level there is the landlord-tenant code, at the federal level there is the Fair Housing act which prohibits discrimination on the basis of race, religion, color, family status, sex or national origin; and the Americans with Disability Act, which prohibits discrimination based on a disability and may require you to make certain accommodations when practical; finally there is the Fair Credit Reporting act which governs how you conduct credit screening checks.

Many of your tenants will know the law. They will know such things as: how much notice you are required to give them to remedy non-payment of rent before you can start the eviction process; if you can charge a pet deposit; and what is the maximum security deposit you can withhold. Not knowing the law can potentially lead to lost time, effort and money.
While this may seem like a lot to learn, there are usually community resources out there that can help. Most areas have real estate investor clubs that often host local area professionals that cover these types of topics. University or Community Colleges often have workshops or non-credit courses on landlord/tenant law. Government agencies may also offer workshops or manuals that can be quite helpful in making sure you are aware of the laws in your area. For example, the state judiciary here has a program called “Lunch –n- Learn the Law”. Held monthly, they invite attorneys in the field to cover various topics and one such annual topic is the landlord/tenant code. They even have a video archive of the landlord/tenant presentation which you can watch here. The Department of Commerce and Consumer Affairs also has an agency that provides information on the code and other related issues. They provide a handbook which can be downloaded here. They also have a hotline and other resources here. I link to these only because going through the material also gives you allot of good general advice which you can use anywhere. Pay special attention to the video.

It is important to note that the resources I cited above reflect the laws and rules in my area, which are almost certainly different from the laws in your area. You must know the laws that apply to you.

The resources are out there, and if not, seek the advice of a professional.