despite efforts by the city of toronto to regulate rooming houses, there is an invisible, unregistered rooming house sector, which are advertised online or on bulletin boards, often in suburban basements which are subdivided into rooms. increasing regulation of rooming houses can lead to a decline in the number of rooming houses that are available, as landlords may choose not to apply for and pay the fees for a city licence, and complete the needed safety requirements (sprinklers, fire escapes, etc.).