(a) If the occupant is a tenant under a written lease or oral rental agreement, the landlord must give a tenant who defaults or holds over beyond the end of the rental term or renewal period at least three days’ written notice to vacate the premises before the landlord files a forcible detainer suit, unless the parties have contracted for a shorter or longer notice period in a written lease or agreement. A landlord who files a forcible detainer suit on grounds that the tenant is holding over beyond the end of the rental term or renewal period must also comply with the tenancy termination requirements of § 91.001.
(b) If the occupant is a tenant at will or by sufferance, the landlord must give the tenant at least three days’ written notice to vacate before the landlord files a forcible detainer suit unless the parties have contracted for a shorter or longer notice period in a written lease or agreement. If a building is purchased at a tax foreclosure sale or a trustee‘s foreclosure sale under a lien superior to the tenant’s lease and the tenant timely pays rent and is not otherwise in default under the tenant’s lease after foreclosure, the purchaser must give a residential tenant of the building at least 30 days’ written notice to vacate if the purchaser chooses not to continue the lease. The tenant is considered to timely pay the rent under this subsection if, during the month of the foreclosure sale, the tenant pays the rent for that month to the landlord before receiving any notice that a foreclosure sale is scheduled during the month or pays the rent for that month to the foreclosing lienholder or the purchaser at foreclosure not later than the fifth day after the date of receipt of a written notice of the name and address of the purchaser that requests payment. Before a foreclosure sale, a foreclosing lienholder may give written notice to a tenant stating that a foreclosure notice has been given to the landlord or owner of the property and specifying the date of the foreclosure.

(c) If the occupant is a tenant of a person who acquired possession by forcible entry, the landlord must give the person at least three days’ written notice to vacate before the landlord files a forcible detainer suit.
(d) In all situations in which the entry by the occupant was a forcible entry under § 24.001, the person entitled to possession must give the occupant oral or written notice to vacate before the landlord files a forcible entry and detainer suit. The notice to vacate under this subsection may be to vacate immediately or by a specified deadline.
(e) If the lease or applicable law requires the landlord to give a tenant an opportunity to respond to a notice of proposed eviction, a notice to vacate may not be given until the period provided for the tenant to respond to the eviction notice has expired.
(f) Except as provided by Subsection (f-1), the notice to vacate shall be given in person or by mail at the premises in question. Notice in person may be by personal delivery to the tenant or any person residing at the premises who is 16 years of age or older or personal delivery to the premises and affixing the notice to the inside of the main entry door. Notice by mail may be by regular mail, by registered mail, or by certified mail, return receipt requested, to the premises in question.
(f-1) As an alternative to the procedures of Subsection (f), a landlord may deliver the notice to vacate by securely affixing to the outside of the main entry door a sealed envelope that contains the notice and on which is written the tenant’s name, address, and in all capital letters, the words “IMPORTANT DOCUMENT” or substantially similar language and, not later than 5 p.m. of the same day, depositing in the mail in the same county in which the premises in question is located a copy of the notice to the tenant if:
(1) the premises has no mailbox and has a keyless bolting device, alarm system, or dangerous animal that prevents the landlord from entering the premises to affix the notice to vacate to the inside of the main entry door; or
(2) the landlord reasonably believes that harm to any person would result from personal delivery to the tenant or a person residing at the premises or from personal delivery to the premises by affixing the notice to the inside of the main entry door.
(f-2) Notice to vacate under Subsection (f-1) is considered delivered on the date the envelope is affixed to the outside of the door and is deposited in the mail, regardless of the date the notice is received.
(g) The notice period is calculated from the day on which the notice is delivered.
(h) A notice to vacate shall be considered a demand for possession for purposes of Subsection (b) of § 24.002.
(i) If before the notice to vacate is given as required by this section the landlord has given a written notice or reminder to the tenant that rent is due and unpaid, the landlord may include in the notice to vacate required by this section a demand that the tenant pay the delinquent rent or vacate the premises by the date and time stated in the notice.