The deadline: 30 days
A landlord must refund the deposit, less any lawful deductions, no later than the 30th day after the tenant surrenders the property (Texas Property Code §92.103).
The clock depends on a forwarding address. A landlord is not obliged to return the deposit or describe deductions until the tenant gives a written statement of their forwarding address (§92.107) - but not having one does not let the landlord keep the money.
The list of deductions
If anything is kept, the tenant must get a written description and itemized list of every deduction (§92.104). Unpaid rent is the exception when it is undisputed.
Keep the move-in inspection, dated photos and invoices. A deduction you can show is one you rarely have to argue about.
Damage, not normal wear and tear
A landlord may not deduct for normal wear and tear (§92.104). Worn carpet in a walkway, light scuffs and faded paint after years of living are wear. Holes in walls, pet damage, burns and broken fixtures are damage.
Cleaning beyond normal use, missing items and unpaid charges under the lease can be deducted when the lease provides for them.
What it costs to get it wrong
A landlord who keeps a deposit in bad faith is liable for $100, three times the portion wrongfully withheld, and the tenant's reasonable attorney's fees (§92.109). Missing the 30-day deadline without the itemized list creates a presumption of bad faith.
A lease clause that tries to waive these rules is void (§92.006).
Advance notice of moving out
A lease may require the tenant to give advance notice of surrender as a condition of the refund, but only if the requirement is underlined or printed in conspicuous bold in the lease (§92.103(b)).
Questions
How long does a Texas landlord have to return a security deposit?
30 days after the tenant surrenders the property, provided the tenant has given a forwarding address in writing (Texas Property Code sections 92.103 and 92.107).
Can a landlord deduct for carpet cleaning in Texas?
Only for cleaning beyond normal wear and tear, or where the lease provides for it. Normal wear and tear cannot be deducted.
What is the penalty for wrongfully keeping a deposit in Texas?
$100, three times the amount wrongfully withheld, and the tenant's reasonable attorney's fees, where the landlord acted in bad faith (section 92.109).
General information about Texas rules, not legal advice. For a specific situation, speak to a Texas attorney.