Different price for more people?

[Therese V.]

I have a 3 bedroom rental that has max occupancy of 6 people. I am renting it starting Dec 1 for $850 to a husband/wife. They came looking at it with her mother and we think they are going to eventually ask to move the mother, her husband and their 2 children in with them.

I am renting the home under market to because it is the middle of winter and to get a better tenant pool. It is a month to month lease. I don't know for sure they want to move the other people in at some point, but just feel that may be the case. Of course, since it is month to month and I would the 2 new adults also fill out rental applications and have a new lease signed.

The question I have is I will want to raise the rent to $1200 if they want to all live there. This is market rent for that size of a home. But, I had noticed another thread here mentioning you can't price differently for more people? Can anyone elaborate on this and how it works with below market rent?

They haven't asked to have more people, I just want to know what's up in case they do (or it happens in the future).