A rental agreement letter is a short written record of an agreement between a landlord and a tenant, used where a full lease is not being drawn up or where something is being agreed during a tenancy. It has real uses and real limits. The limits matter, because a letter used where a lease belongs leaves both sides relying on statutory defaults nobody chose.
Where a letter genuinely works
Confirming a variation during a tenancy: a rent change agreed, a new occupant permitted, a payment arrangement, permission for an alteration. In each case the underlying lease continues and the letter records what changed, when it takes effect, and that both parties agree. Signed by both and dated, that is a perfectly good record of a variation.
What it has to contain to be worth anything
The parties, the property, exactly what is being agreed, the date it takes effect, whether it is permanent or for a stated period, and signatures with dates. Vague letters produce the argument they were written to prevent. If it changes the rent, state the new amount, the first payment it applies to, and that all other terms continue unchanged.
Where a letter is the wrong document
Starting a tenancy. A letter will not carry the deposit terms, the disclosures required by federal and state law, the maintenance allocation or the notice provisions, and in most states a longer fixed term needs a proper written agreement to be enforceable as such. A tenancy begun by letter runs on statutory defaults, which are rarely what either party would have chosen.
Keep it with the lease, not instead of it
A variation letter is only useful if it can be found beside the agreement it varies. File it with the lease, reference it in the tenancy record, and if several accumulate, consider replacing the whole document at renewal. Three letters and an original lease is a tenancy nobody can state the current terms of without reading four documents.
Questions people ask about rental agreement letter
Can a tenancy be created by letter?
A periodic tenancy can arise informally, but a letter will not carry the disclosures and terms a proper agreement does, and longer fixed terms generally need writing.
Does a rent change need a new lease?
Usually a signed variation letter suffices, subject to any statutory notice requirement for the increase. State the new amount and the first payment it applies to.
How many variations before replacing the lease?
When somebody cannot state the current terms without reading more than two documents. Renewal is the natural point to consolidate.