Deep-soak your lawn. When you do water your lawn, do it just long enough for water to seep down to the roots where it won't evaporate quickly and where it will do the most good. A light sprinkling which sits on the surface, will simply evaporate and be wasted. A slow steady fall of water is the best way to irrigate your lawn. Water during the cool parts of the day.
Early morning is better than dusk since it helps prevent the growth of fungus.
Don't water the gutter. Position your sprinklers in such a way that water lands on your lawn or garden, not on concrete, where it does no good. Avoid watering on windy days when much of your water may be carried off before it ever hits the ground. Check for leaks in pipes, hoses, faucets and couplings. Leaks outside the house may not seem as unbearable since they don't mess up the floor or drive you crazy at night.