They get you coming and going. You can't win for losing.
A local water district is seeking an 18% rate increase because their revenues have gone down. Whether it's because of the wet winter and mild summer we had or because of water conservation efforts or because of the bad economy, people are using less water and the district isn't making enough money.
It's similar to gas taxes. If you drive a high-mpg vehicle, you don't get dinged with high gas taxes. However, if everybody drove high-mpg vehicles, we'd use less gas--which means the states and feds would get less gas tax revenue. Problem is, the roads would still need maintenance, so the taxes would have to be increased!
If everyone does it, there's no economic benefit to conservation.