EXPENSES AND ASSESSMENT OF COSTS OF WATERMASTER.

(a) Except as provided by Subsection (e), the trial court shall assess the costs and expenses of the watermaster and his staff against all persons receiving an allocation of the water in judicial custody. The court shall assess the costs and expenses monthly or at other time intervals ordered by the court.

(b) The court shall assess the costs and expenses on the basis of:

(1) acreage;

(2) acre-feet of allocated water;

(3) per capita; or

(4) any other formula the court, after notice and hearing, determines to be the most equitable.

(c) During the pendency of an appeal, the trial court, in its discretion, may assess costs against some parties on one basis and against other parties on another basis.

(d) The costs and expenses are not to be taxed as ordinary court costs, but are to be considered costs necessary to protect the rights and privileges of the parties receiving allocations of water during the litigation and are to be paid by those parties.

(e) The court may not assess costs and expenses under this section against:

(1) a holder of a non-priority hydroelectric right that owns or operates privately owned facilities that collectively have a capacity of less than two megawatts; or

(2) a holder of a water right placed in the Texas Water Trust for a term of at least 20 years.