Tex. Water Code § 57.058

In districts which have elected boards, there shall be five directors on the board. The initial elected directors shall draw lots to determine which two initial directors serve two-year terms and which three initial directors serve four-year terms. In countywide districts, one director shall be elected by the electors of the entire district and one director elected from each county commissioners precinct by the electors of that precinct. In other districts, all five directors shall be elected from precincts within the district to be established by the commissioners court.