A lease addendum is a supplemental document attached to a new or existing lease that adds or changes specific terms without rewriting the whole agreement. Common examples cover pets, parking, appliances, a smoking policy, or a required disclosure. Once signed by both parties, an addendum carries the same weight as the lease it modifies.
Addenda keep the base lease clean while letting you tailor terms to a unit or situation, and they’re the right tool for a disclosure your jurisdiction requires. To avoid ambiguity, an addendum should reference the lease it belongs to, be dated, and be signed by everyone on the lease. (An “amendment” changes existing lease terms while an addendum usually adds new ones, though the practical effect is similar.)