(Editor's Note: This article was originaly published on March 29, 2007.)
Save your dishwater. Put a couple of dish pans in the sink to catch your wash and rinse water, as well as water from washing your hands or anything else. I keep a few five gallon buckets outside the door to empty them into so that I do not have to run in and out so often. The one question I hear every time I mention this is, "Will the detergent hurt my plants?" No. I read in a catalog once that if the order arrives dry, add a bit of dish soap to the water to help revive the plants. My Mom remembers where her Grandmother dumped the wash and dish water as being the lushest area around. If you are worried about detergents, dilute them with the rinse water. The only thing that may hurt plants, especially tender ones, would be salt from soft water. If you are really good, you may be able to figure out how to save bath/shower water effectively, or even laundry water (do not use for a couple of days if bleach has been used, and fabric softener may be a problem).
Have every available bucket along drip-edges to catch rain water. Rain water has nitrogen and other nutrients in it, and the ph balance is perfect, so it is always the best to use for watering. If you save it, be sure to check for mosquito larva daily and empty immediately if you see any (they are little squiggly things; you may need to tap the side of the bucket to get them moving so you can see them).
Place a bucket or pan to catch the drip water from your air conditioner. This can provide quite a bit of water! Also, if you use a dehumidifier, use the water from that. I even catch the drip water from the furnace in the winter; freezing is generally not a problem.
If you have a small pool, use the water from it. I have a large tub for my son to play in. I water with it in the evening, and then fill it back up so it will be warm the next day for him to play in. Another advantage to this is that the chlorine has a chance to evaporate, which is better for both him and the plants.
If you have a pond, use some water from it and replace with fresh. This is especially good if you have fish, as the fish waste is good for the plants, and it helps keep the nitrogen and salts, etc. from building up in the pond. You may not want to use too much at any one given time if you do have fish, so as to prevent a problem with chlorine and temperature. This would depend on the size of the pond and the type of fish. I have about a one hundred gallon pond and twelve goldfish. I have emptied it a bit over halfway and refilled it with no problem.
I check to see what needs watering the most and water there, usually a small area, really well. For most plants you can wait until the soil dries out. I do occasionally have to use tap water, but only when really needed. Remember when watering, water deeply so that the roots will go deep rather than stay shallow where they will easily dry out. It is best to water in the early morning. If you cannot water then, wait until evening, though this allows more chance for fungus to thrive. When I do use a hose to water, I prefer to not use a nozzle, but have the water medium-low and put it at the base of the plant. That way, water is not taken away by the breeze or evaporation. It seems to go faster and take the water right where it is needed. If there is plenty of compost in the soil, it soaks right in. If it is particularly dry or the soil not so good, you may need to work the surface some and turn the water lower or mist it first so the water does not just run off.
For potted plants, I like to sit them in a pan of water so that they do not dry out so fast. Make sure it is not too much at a time, so that the water does not get stagnant and the roots do not rot.
Mulching well goes without saying, though most people do not know or do not bother with putting enough on to do the job. Mulch should be three to four inches deep. A lot of good compost in the soil helps to hold moisture.
Keep your garden weeded. Weeds steal much needed water (and nutrients) from your plants.
Avoid chemical fertilizers. They put on a flush of new growth, and new growth needs more water than established growth (and is more prone to pest damage because it is tastier). Chemical fertilizers are to plants what potato chips are to people. They make you bigger faster, do not give necessary nutrients, and make you thirsty.
These are good habits to keep even when there is not a watering ban or drought. If you have city water, you have to pay for it, so you had might as well get as much use out of it as you can. Even if you have a well, remember, WATER IS NOT AN ENDLESS RESOURCE.