Last year, then-presidential hopeful Carly Fiorina weighed in on the water issue and termed it "a man-made disaster" and pinned the blame on "liberal environmentalists."
"This is sloganeering," said Jeffrey Mount, a senior fellow at the Public Policy Institute of California's Water Policy Center. "In fact, the environmental allocation during the drought has been tiny. The environment takes a bigger cut than everyone else."
Valadao has tried to distance himself from Trump. The Republican lawmaker, who was first elected to Congress in 2012 with nearly 58 percent of the vote, represents a district where more than 70 percent of the residents are Latinos.
"I've not gotten involved in that Trump campaign at all," said Valadao, who comes from a dairy farming family and is the son of Portuguese immigrants.
Huerta was endorsed on Friday by President Barack Obama. The congressional candidate is the son of Delores Huerta, a labor and civil rights leader who co-founded what later became the United Farm Workers.
Indeed, the Democratic Party is hoping to pick up House gains in Tuesday's general election and believes Valadao's seat may be more vulnerable this year.
"Donald Trump is the leader of the Republican Party and he (Valadao) failed to distance himself from Trump early on," said Huerta, who went on to criticize Trump for making negative remarks about Mexican immigrants.
Meantime, Valadao last year introduced a House bill (HR 2898) that would have eased the environmental rules. The bill passed the Republican-controlled House but hasn't been approved by the Senate, where Barbara Boxer and Dianne Feinstein — the two Democratic senators from California — oppose it. Prior to that, Valadao had a 2014 water bill that cleared the House but didn't pass the Senate.
"His bill hasn't gotten anywhere," said Huerta. "It failed to get approval from the Senate so now he's blaming the California senators. Whereas two years ago he was blaming the Democratically elected Senate."