The most important source of information about a residential tenant’s rights and a landlord’s responsibilities is the written lease agreement. Some landlords prefer oral agreements, but it is more common for them to require the tenant's signature on a written lease—and a written lease protects the tenant more than an oral agreement. Be sure to read the lease carefully before you sign it.

A residential landlord’s ability to charge late fees generally depends on the specific language in the written lease agreement; the state’s landlord-tenant laws that may limit the amount of late fees the landlord can charge and the circumstances in which they can be charged; and the state's contract law.

Contract law in most states recognizes an implied duty of good faith and fair dealing between parties to a contract, and a residential landlord who charges late fees because the tenant is an hour late paying the rent may be in breach of the landlord’s implied duty of good faith and fair dealing—unless, for example, the lease agreement specifies an hour (12:00 p.m.) of the day by which rent is due and states that time is of the essence.

In North Dakota, the written lease agreement is indeed a crucial document outlining the rights of residential tenants and the responsibilities of landlords. Tenants should thoroughly review and understand the lease before signing, as it provides more security and clarity than an oral agreement. Regarding late fees, North Dakota law allows landlords to charge them as specified in the lease agreement. However, the amount and conditions under which late fees can be imposed may be subject to state regulations to ensure they are reasonable. North Dakota's Century Code does not specify a maximum late fee but does require that any fees charged be agreed upon in the lease. Additionally, the concept of an implied duty of good faith and fair dealing is recognized in North Dakota contract law, which means that landlords are expected to act fairly and not impose late fees in an unreasonable or punitive manner. For instance, charging a late fee for rent that is only an hour late without a clear stipulation in the lease that 'time is of the essence' could potentially be seen as a breach of this duty.