High efficiency toilets use 1.28 gallons of water per flush rather than the standard 1.6-gallon models. It's not actually a huge savings, but it definitely adds up. California expects the law to save about 8 billion gallons of water each year.

High efficiency toilets come in dual flush and single flush options. Personally, I think the dual flush makes much more sense (use only the water you need). I first encountered these Australian-invented toilets in New Zealand and wondered why they hadn't made their way to the United States.

Around the world, more dual flush toilets are sold than single flush models. In the United States, we're finally catching on, and the two models now sell almost equally.

Hopefully, California's lead will encourage other water-scarce states, such as the southwestern states and even drought-ridden Georgia, to pass similar legislation.