Look at your tenancy agreement to see what it says about guests or visitors. It is illegal for the landlord to unreasonably restrict access of your guests or temporary visitors. If utilities are included in your rent, and you have guests who will be staying for awhile, you can offer to temporarily pay extra to help offset the costs, but your landlord can't tell you that your visitors must leave unless they are disturbing others. If your visitor stays for a long period of time, or has joined the tenancy without the landlord's consent, it is possible for the landlord to evict you. You have the right to dispute such a notice at the Residential Tenancy Branch. The landlord would have to prove that the number of people occupying the rental unit was unreasonable or that you were in breach of the tenancy agreement.
If you live in non-profit housing, you can have guests - your guests are not the business of your landlord. However, if they stay too long and it looks like they have movied in, you may be in breach of your tenancy agreement. Remember too, that to qualify for a rent subsidy, you must report the income of all residents in the unit. So if it looks like the guest has become a permanent resident, their income must be reported and this can affect your rent subsidy.
Read Chapter 7 of our Tenant Survival Guide for additional information on guests and visitors.