Something that farmers could do, when I have my farm I plan on doing this, is to leave every other row unplowed, so the grass and plant matter conserves water. However all the equipment would have to be switched, so it's probably not as viable, but it works well for our garden.
I save all the water in my glasses at the end of the day and use them to water plants, or put in a pot with soap and boil to release the crud.
You could also create a rain catching system using your gutters and collect it in a barrel, or dig trenches and irrigate that way.