Tex. Water Code § 13.504

If, during the 90-day period preceding the installation of individual meters or submeters, an owner, operator, or manager of an apartment house, manufactured home rental community, or other multiple use facility has increased rental rates and the increase is attributable to increased costs of utilities, the owner, operator, or manager shall immediately reduce the rental rate by the amount of the increase and refund all of the increase that has previously been collected within the 90-day period.