Most people (rationally) do not spend much time following policy debate.
Most people (rationally) take the actions of the government at face value.
There's just not a large contingent of people out there who are like, "Wait, this is obvious bullshit, OH now I understand that I've been directed to go figure out an actual way to save water." The people who understand that it's bullshit already know better ways to save water. The people who don't know better ways to save water just take it at face value that the government is providing them with reasonably effective approaches to save water.
This isn't a knock on the intelligence of the general public. For the most part, government does work this way. They are correct about the general pattern. Environmentalism seems particularly prone to counterexamples. It is unreasonable to expect busy people who understand correctly that they have very little marginal impact on policy to have dug into policy wonkery enough to know that environmentalism is unusually prone to these kind of ineffective actions.
Perhaps gov Brown saying he'll skip a shower or two would be more symbolic but also transparent.