Precipitation is a fickle phenomenon, with some years dry and others very wet. Even if you are in a region that doesn't seem to have trouble getting the water it needs, conservation is always a good idea. It helps preserve drinking water in those areas where city supplies are used for both consumption and irrigation, and it helps stretch canal supplies in areas that use pressurized irrigation for landscaping. If you have not already done so, start making changes to your golf course to cut back on the amount of water you need to keep the course looking green.
Native Drought-Resistant Grass
Any parts of the greens that need to be reseeded or replaced should have native drought-resistant grass laid down. If you're in a region where there really are no native lawn-type grasses, at least go for the low-water drought-resistant species. Native grasses are better suited to the natural rainfall patterns in the region, which means you don't have to over water anything just to keep the course alive. Drought-resistant grasses survive for longer without a lot of water should precipitation levels drop. And low-water grasses just don't need a lot of water in general; in fact, you might be able to get away with very little sprinkler use with this type of grass. All of those qualities are perfect for lowering your water bills and consumption levels.
Up-to-Date Sprinkler System
If it's been a while since you updated your sprinkler system, it's time to do so now. New systems use the latest in water-conserving technology, and if your current system is really old, then you could be releasing too much water in too long a time compared with what you could have installed now. If your sprinkler system is already fairly new, but you think you could cut back more, see about installing flow devices to limit the water that is released.
Never leave the timer alone for long stretches of days or weeks. Always monitor the weather and turn off that sprinkler timer if it rains. There is no sense in letting the sprinkler run if you know a storm's coming in that afternoon.
You could be in the best region of the country for predictable, abundant rainfall, and it would still be a good idea to conserve water during those times when you do have to use the sprinklers on your golf course. It makes sense for your water bills, and it makes sense for the environment.