House Rules, Apartment Regulations, and Community Policies are all the same thing — rules of the landlord. Even though these are not usually in the lease documents you signed, they are often made a part of the lease by reference (if the rules are not referenced and you are not given a copy when you sign the lease, then the rules legally should not be applied to you).
Before you sign the lease, ask for a copy of the rules. If the rules have not been written down, ask the landlord to write them down, and have the landlord sign and date the document. Having written rules will prevent the landlord from changing the rules in the middle of your lease. In general, most house rules are enforceable as long as they do not illegally discriminate. See Discrimination. For example, sometimes a landlord will improperly require families with children to occupy certain units or require the tenant to lease a unit with more bedrooms than necessary. A landlord is allowed to set reasonable rules regarding occupancy, but at some point these rules could violate fair housing laws.
Rules may be unenforceable if they are completely unreasonable. For example, some lower courts have considered a broad curfew on adults unreasonable. But, if you feel a landlord’s rules are unreasonable, it may be safer to follow them temporarily and move rather than attempt to challenge them, unless you have an attorney or tenant organization to back you up. It is never good to be a defendant in an eviction case (even if you win court records will show that a case was filed against you).
But most all rules clearly made a part of the lease are likely to be upheld by the courts. And if you violate a house rule, even once, the landlord could attempt to terminate your right to possession of the premises and attempt to evict you. Certainly, a minor violation is likely to be overlooked by a landlord; however, be aware that you take risks when you ignore the rules. A landlord can fail to renew a lease or may terminate a month-to-month lease by giving a 30-day notice for most any reason and a court will probably uphold that decision. There are some exceptions: Retaliation, Discrimination.
Rules easily changed in month-to-month leases, but not in the middle
A landlord can also change the rules easily if you are renting month-to-month by just giving you 30 days advanced notice of the change. That may seem unfair because it is often expensive to move and time consuming to find another place that may be more acceptable. Since when does fairness matter in landlord-tenant relationships?
A landlord cannot change the rules in the middle of a lease agreement without your agreement. Ultimately, it is your decision whether to accept the new rules. If you accept them, then the landlord is more likely to renew your lease when it expires. However, if you fail to accept the change in the rules in the middle of the lease, a landlord may fail to renew your lease or charge you more rent in the future when the lease expires. This is likely to be legal.