It is fairly common for a tenant to split the costs of renting by bringing in a permanent guest, or “undertenant”. The Residential Tenancies Act includes no remedy for a landlord in such cases, because it does not consider it to be unlawful. A landlord can neither raise the rent to reflect the additional utility use and wear and tear on the rental unit, nor prevent the tenant from having the roommate, as long as local municipal bylaws on occupancy standards are respected.