Tenants have an obligation to pay rent on time. However, they also have protection under the law when they are late. Texas law requires landlords to be fair and reasonable when assessing late fees. If they are not, you could be awarded monetary damages if you take them to court.
Section 92.019 of the Texas Property Code governs the policy of late fees for rent. It requires landlords to state in your lease the amount you will pay in late fees if you pay your rent late. The fee must be reasonable and the amount set must justify the effort the landlord exerts to collect your late rent. While there is no specific amount stated in the Texas Property Code, the universally accepted fee is five percent of your rent amount.
You can sue your landlord if you feel he took advantage of you and charged excessive amounts. This rule applies whether or not you actually paid the late fees. If you win your case, the landlord must pay you a sum of up to $100 and three times the amount of the late fees, as well as reasonable attorney's fees
Protection From Default
If you carry late fees on your account, a landlord cannot deduct your late fees from rent payments and therefore place you in default for nonpayment of full rent. For example, say you owe $1,000 for rent and a $50 late fee. You pay $1,000 for rent but not the fee. Your landlord cannot apply $950 to the rent and pay off the late fee, thereby making your rent payment incomplete.