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It may be surprising to learn (well, I was surprised, anyway) that toilets use 30-40 percent of the water in our homes, far exceeding all other single activities. Delivering water takes energy, electricity to be specific, since it’s pumped to our homes from great distances.
While we do take advantage of the natural fall from the Sierras, we still use over 10 percent of our total state energy budget moving water. Making electricity generates carbon in many cases (we do have some hydroelectric power in the state as well as some nuclear) and this increases global warming as well as the acidity of the oceans just to mention two of the effects we’re aware of.
As of Aug. 1 this year, East Bay Municipal Utility District (EBMUD) has us on a Drought Emergency Rate Schedule for water service. You’ve probably heard. Families will be expected to keep their use under 172 gallons per day or pay at a higher rate. The base rate is $2/100 cubic feet of water and goes up to as much as $3.05 if you can’t get your teenager out of the shower in something under an hour.
With all this in mind, I suggest that you take on the, relatively simple, task of replacing one or more of your toilets. It’s actually not that hard.
Sanitation Updates 
It’s actually one of the simplist home improvemnets I’ve ever done. About an hour of work to get it replaced. There may actually be some incentives or pricebreaks in your state / province, so check prior to purchase.
We have also just made our existing toilet more water conserving by taking empty milk jugs, filling them with water, and putting them in the tank. This displaces a lot of water and is thus reducing consumption. There is a toilet out there I have heard about, and am researching. It is only 1.28 gpf, which is the lowest i’ve heard of: http://eartheasy.com/store/proddetail.php?prod=N2225
What do you think about that toilet?