The Residential Tenancies Act automatically applies to some living situations. This means that even if the tenant or the landlord does not know about the Residential Tenancies Act, the law applies to them anyway.
Sometimes the lease will specifically reference the Residential Tenancies Act and sometimes the lease won’t mention the law at all. The law will still apply regardless of whether it is mentioned in the tenancy agreement.
Tenants cannot waive any of the rights that they’re given under the Residential Tenancies Act. For example, if the lease says that the landlord can give a monthly periodic tenant a one week notice to move out if the rent isn’t paid, then that part of the tenancy agreement is not enforceable because the law says that a tenant in that situation should get a 14 day notice.