I was researching about investing in apartment buildings and I was wondering if there is any way to avoid renting to tenants who are on welfare. Legal answers only please, my grandfather and friend's father had very negative experiences renting to people on welfare so I don't want to hear any moralizing about discriminating against poor people.

Really simple Earl, invest in high end apartment buildings! :D

There are federal laws about discrimination when renting, and there are additional state laws.
I studied them in the real estate agent course.
I won't reinvent the wheel here. You can find them. It would take an hour of typing.

Renting to anyone can be not only problematic, but there often isn't a nice neat law to cover the dispute, and you end up in court, or lose just by not being paid. Paying can't be forced; only eviction can, and that can happen weeks after a tenant stopped paying. Retaliation isn't allowed either.

Sure you want to own apartment buildings? The recession and bank clampdown on mortgages was great for landlords, but that is showing signs of being over, and there could be a glut.

My advice: buy a building nice enough to either rent or turn into condos.

First, that is not how this site works. When you post a question you open yourself up for any comment as long as it doesn't violate our rules. You DO NOT dictate who can respond or how they respond.

That being said you are allowed to do a credit and background check of prospective tenants. If they have poor credit or previous landlords have had bad experiences, then you can reject them as tenants. You will have to provide justification if sued.

But the best answer is to invest in higher end buildings that are out of the market for lower income renters.