Tex. Spec. Dist. Code § 6613.152
(a) The interest and sinking fund consists of taxes collected for the fund. Money in the interest and sinking fund may be paid out only to:
(b) The maintenance and improvement fund consists of money collected by assessment or other sources for:
Added by Acts 2015, 84th Leg., R.S., Ch. 855 (S.B. 1162), Sec. 1.01, eff. April 1, 2017.