I am interested in this subject also. I live east of Dallas in Rockwall and I have a 25000-30000 sq. ft. yard with a sprinkler system. I have 144 sprinkler heads on 12 different "stations". It scares me that someone above said they water each area 4 HOURS and another 1 HOUR per week. If I did that there is no way I could afford my water bill. Don't get me wrong, you may need to water that long but, ****, I water about 25-30 minutes in each station once a week and I can EASILY use over 30,000 gallons of water a month.