Tex. Water Code § 58.304

The board, on or as soon as practicable after a date fixed by standing order of the board, shall estimate the expenses of maintaining and operating the district's water delivery system for the next 12 months. The board may change the 12-month period for which it estimates the expenses of maintaining and operating the water delivery system by estimating such expenses for a shorter period so as to adjust to a new fixed date and thereafter estimating the expenses for 12-month periods following the adjusted fixed date.