Last summer, during a dry spell, the plants' main water source was city water. Although they were grateful for some moisture, they didn't look too healthy - with all the chlorine and hard water stuff...especially the rhododendrons. Lately, I've been researching compost tea which gave me a great idea. The instructions state: if you are going to use city water, set it out for 24 hours to let the able chemicals evaporate - like chlorine.
There was a small pale of water that was brown due to the leaf litter steeping in it for a few days. Instead of throwing it out, I watered a nearby plant with it. It seemed to REALLY like this brew...so I found a bucket and filled it with water and leaf litter to set out overnight. Every morning I'll give the herbs and veggies a cupful of water...they have responded amazingly well!
Not only am I conserving the amount of water I give them, I'm giving them a mild nutritional boost every morning...like a power drink. (post note: the mosquitos REALLY love the tea too, so put a wet towel or a screen over the bucket so you don't have to share your yard with blood suckers)