On another thread Nicko talked about his rain barrels.
Rain barrels aren't a bad way of recycling water. But they do have some downsides. First and foremost, of course, is that they only fill when it's raining. And when it rains good, one barrel isn't enough, as they fill rather fast. Still and all, one or two barrels is certainly better than nothing.
But considering how hot it's been all over the country, and how many areas are suffering from little rain, you might want to consider other methods as well.
Probably the most overlooked is your air conditioner. We tend to see those little drops and shrug it off. But air conditioners, depending on the humidity levels, waste a lot of water. I have a window unit in my kitchen, for instance, that currently fills a 5 gallon bucket daily. That's a bunch of water you can use in your garden. Friend of mine redirected his condensate line from his central air and fills a 32 gallon barrel every day.
Ever think about how much water you throw away from dish washing and showers? Gray water, as it's called, is perfectly OK for garden use. You can easily redirect it to the gardens. Best bet is to use a tile pipe in the garden itself, and it will act as an overgrown soaker house.
Speaking of soaker hoses, do you use them? If not, you should. The greatest waste is to stand in the garden with a hose, as you use far too much water that way. There are two lose points. First, you are putting water where it doesn't have to be. And, second, you lose a lot to evaporation right off the water stream. Soaker hoses put the water directly where it's needed, and at a rate easier for the ground to absorb.
BTW, you can configure your water barrels so they feed directly into soaker hoses, getting the best of both worlds.
Ultimately, a drip irrigation system is the ideas watering method. Such systems can be a little more expensive to install, and you have to understand the use of regulators and manifold, and the various kinds of emmiters used. But they pay for themselves in a relatively short time from water savings. Contrary to conventional wisdom, drip irrigation is ideal for container gardens, because you place an emmiter right in the container, and there is no waste.