I have  given up baths; instead, I take five-minute or less showers along with a bonny blue bucket, which is dumped when full in my (too many) large pots. I keep a plastic pitcher by the kitchen sink to harvest any water I would throw out -- boiled water from the kettle for morning tea, for example. The pitcher is then poured into pots. Fancy nozzles are now on all hoses. I drip drip drip into pots from the hoses now. I live in LA and would like to stay within the first tier of water allocation but I'm not going to make it -- not in summer. We have irrigation, most of it underground. Will I have to kill off some of the garden? Oh I hope not. (It's only a 5,000 sq.-foot lot, but densely planted.) 

I'd been thinking about it for a long while; I wanted to sink a cistern in my yard to collect rainwater from the roof.  Last year I ended up with a 5000 gallon tank buried in my back yard - it was a long process to get to that point and since the permit was signed off on, we have had one decent rainstorm - last March 2014,  3".  That 3" allowed me to water my yard -at no cost- for 6 weeks.  It will take an awful long time to pay off the initial cost of the cistern but it really does feel wonderful when I use 'free' water and over time it will make a difference and pay for itself.

I also bale my bathtub after a bath or shower to re-use the pretty clean 'greywater' water.  The location of my clothes-washer is too 'downhill' to be able to use that water for any garden purpose....until I come up with a new plan.  "Keep calm and carry on".