As you may know, federal law prohibits selling, repairing, modifying, trafficking in, speaking of, or using a new shower head that actually delivers water in a form other than a light mist.
A company in Arizona has circumvented the federal regulations by concocting a replacement shower-head assembly containing THREE heads, each delivering the federal maximum. This results in a mostly acceptable shower.
Here's a story about this breakthrough invention:
The story goes on to inform you how these 'water saving' shower heads work and how you can gain access to the actual part restricting the flow so that it can be removed and, of course, replaced should the part ever wear out or not adequately restrict water flow (nudge-nudge, wink-wink).
P.S. The best way to conserve a scarce resource is to let the marketplace price the product according to the laws of supply and demand. Inasmuch as most water systems are run by agencies of government, this concept is completely impossible to understand.