A human can go for more than three weeks without food (Mahatma Gandhi survived 21 days of complete starvation), but water is a different story. At least 60% of the adult body is made of it and every living cell in the body needs it to keep functioning.
You cannot raise the rent if you and the tenant have agreed, usually in a written lease, on a certain amount. Usually, you and the tenant will agree on a certain amount for a specific period of time. Once that time period ends, you can raise your rent with 30 (thirty) days written notice. If you and the tenant never agreed on a specific period of time, you can usually raise the rent with 30 (thirty) days written notice.
Properties that have no rent stabilization will usually be fairly straightforward. The landlord must first formally give 30 days of notice to the tenant. If the tenant does not leave, then the landlord must serve the tenant with a Notice of Petition for eviction. A court date may then be set for 5-12 days after the date of service. At the court hearing, the judge may set a date by which the tenant must vacate the premises.