Free Lease Addendum Templates

What Is a Lease Addendum?

A lease addendum is a written supplement attached to an existing lease that adds new terms, disclosures, or rules without rewriting the original instrument. Examples include the federal Lead-Based Paint Disclosure under 42 U.S.C. § 4852d for pre-1978 target housing, bed bug disclosures under Cal. Civ. Code § 1954.603 and NYC Admin. Code § 27-2018.1, mold disclosures under Tex. Prop. Code § 92.201, pet and assistance-animal addendums governed by HUD's 2020 FHEO Notice on the Fair Housing Amendments Act, and crime-free housing addendums required for federally assisted housing under 24 CFR § 5.857 and 42 U.S.C. § 1437d(l)(6).

Once signed by landlord and tenant and incorporated by reference into the main lease, the addendum becomes part of the integrated agreement under the parol evidence rule (Restatement (Second) of Contracts § 213). Courts apply the same rules of construction to the addendum as to the main lease: specific terms control over general terms, and the parties' last expressed intent controls conflicting provisions absent a contrary priority clause. Properly drafted addendums survive lease renewals and holdover tenancies under URLTA § 1.401, importing every fee, restriction, and disclosure into the renewed term unless the renewal instrument explicitly drops them.

Most residential leases include at least two mandatory addendums. The federal lead-based paint disclosure applies to all target housing built before 1978 and carries civil penalties up to $19,507 per violation under 24 CFR § 30.65. State disclosure addendums vary: California requires bed bug disclosure under Civ. Code § 1954.603 and mold disclosure under Health & Safety Code § 26147; New York City requires annual bed bug disclosure under NYC Admin. Code § 27-2018.1; Florida requires radon disclosure under Stat. § 404.056(5); Illinois requires radon disclosure under 420 ILCS 46.

Addendum versus amendment versus rider

An addendum supplements: it adds new terms the original lease did not address. An amendment modifies: it changes existing lease provisions and replaces the affected clauses. A rider is functionally an addendum, used in some commercial practice to describe landlord-drafted supplements attached at signing. The labels matter for evidentiary clarity, not enforceability; courts apply the substance of the document. The drafter should identify the right instrument: a rent-change document is an amendment because it modifies an existing obligation, while a new pet policy is an addendum because it addresses a subject the lease did not cover.

Integration clauses and conflict resolution among multiple addendums

Standard residential leases include an integration (merger) clause stating the lease and attached exhibits constitute the entire agreement and that no oral or written representations outside the document modify it. When the lease has multiple addendums, conflicts among them are resolved by the contract-construction rules in Restatement (Second) of Contracts § 203: specific controls over general; later-dated controls over earlier; handwritten controls over typed; typed controls over preprinted form language. Best practice is to label every addendum (Exhibit A through Z) sequentially, reference each one in the main lease's integration clause, include an explicit priority clause in each addendum, and execute each addendum with separate signatures and dates to defeat any later claim that the addendum was not part of the original bargain.

Types of Lease Addendums

Choose the addendum that matches what you are adding. Each variant is drafted for a specific purpose and cites the governing statutes where applicable.

Addendum vs. Amendment

The two are often confused but serve different purposes. Pick the right tool for the job.

How to Attach an Addendum

A clean addendum has four parts: identification, incorporation, the new terms, and signatures.

State-Law Considerations

State law drives what addendums are required and how they must be delivered. A few examples:

• California: Bed bug disclosure required under Civil Code §1954.603; mold disclosure under Health & Safety Code §26147; just-cause lease terms under AB 1482 must be re-acknowledged.
• New York: Annual bed bug disclosure (DHCR form NYC-RA-79) required under NYC Administrative Code §27-2018.1.
• Texas: Mold disclosure under Property Code §92.201; lead paint for pre-1978 housing under federal rule; optional flood disclosure under §92.019.
• Florida: Radon disclosure required under §404.056(5); mold and bed bug addendums recommended but not statutory.
• Oregon: SB 608 (ORS 90.323) rent-increase notices must reference the addendum, and just-cause termination addendums (ORS 90.427) are common.

Federally Required Disclosures

Two federal rules generate mandatory addendums for residential leases:

Frequently Asked Questions

Common questions about attaching, enforcing, and terminating lease addendums.

Official Resources