Does a North Carolina rent increase notice need to be in writing?

Yes. North Carolina requires a written notice for any rent increase on a month-to-month tenancy or at the end of a fixed term. North Carolina has no statewide advance notice specific to rent increases. NCGS 42-14 sets 1-month notice for year-to-year termination; 30-day month-to-month notice is the default practice for rent changes. No state rent cap. An oral notice is generally not enforceable; the tenant can refuse to pay the increased amount and the landlord cannot evict for nonpayment of an unwritten increase. The written notice should state the current rent, the new rent, the effective date (which must be after the statutory notice period), and the landlord's signature. Delivery follows the same service rules as other landlord notices: personal delivery, substituted service, or posting plus mailing.

Source: NCGS 42-14 (30-day month-to-month termination default)