The water measure attracted the most visibility and campaign funds, drawing support from business and environmental groups alike. Some conservatives oppose using the state's savings account to finance large-scale construction projects while others were concerned the money could be misused.
Parker County voters approved the measure, listed on the ballots as Proposition 6, by a 2-1 margin.
Gov. Rick Perry applauded Texans' approval of using $2 billion in reserve funds to help the state meet the future water needs of its booming population and economy.
Perry said "the people of Texas made history." He said the vote will ensure "we'll have the water we need to grow and thrive for the next five decades, without raising state taxes."
The proposition will move $2 billion from Texas' rainy day fund to its water infrastructure fund.
The money would help defray the borrowing costs on large-scale water infrastructure projects, including creating reservoirs, laying new pipelines and replacing older ones.
Texas House Speaker Joe Straus called the results "a resounding and overwhelming victory" for the bipartisan campaign that he championed. In early results, more than 75 percent approved the measure.
"I think you saw stakeholders who don't always agree with one another come together in a very collaborative way," Straus said at a campaign party in a downtown Austin bar. He called for the state comptroller to transfer the funds as soon as possible.
Environmentalists also praised the result.
"We're thrilled that Texas voters have chosen to invest in Texas' water future," said Luke Metzger, director of Environment Texas. "Texas is in a water crisis, caused by drought and made worse by wasteful water use."
Earlier Tuesday, Connie Dean was part of a slow trickle of West Texans voting at a Lubbock elementary school. The 74-year-old retiree didn't have any issue with the new voter ID requirements, but she wasn't so sure she liked tapping the state rainy day fund.