I recently saw a statistic about water use around the world. It was a simple breakdown, showing that 70 percent of the developed fresh water on the planet is used for irrigation, while the remaining 30 percent is used for nonfarming purposes, such as residential and industrial uses.

This breakdown stuck in my head because it reminded me of how we use water around our homes here in Southern California. Seventy percent of the water delivered to our homes is used to irrigate our outdoor landscapes. More than two-thirds of the water we receive through our faucets and hose bibs. Water fit for cooking, bathing and drinking is simply spread outside in the name of a showpiece lawn and flowerbed.

I have another worldwide figure to share with you. Southern Californians use about twice as much water as Europeans do. And here's one more. Studies show that typical homeowners in the Southland use two times as much water on their lawns as needed. The math couldn't be simpler. It's not hard to see where we can make the biggest impact if we want to conserve more water.

Recently, Gov. Arnold Schwarzenegger issued a plea for Californians to trim an additional 20 percent off of their water use by 2020.

What the governor has realized is that factors independent of weather will continue to create water-supply issues for our region. You may have heard of the Delta smelt, an endangered fish about the size of your pinky. This year, the smelt's precarious status has meant the loss of about 30 percent of the Southland's imported water supplies from the State Water Project.

Hopefully, the smelt will rebound. But the federal Endangered Species List is a long roster. Before the smelt, there was the winter-run Chinook salmon, the steelhead trout, the humpback chub. There's been the Stephen's kangaroo rat and the least Bell's vireo. These species have all hindered the water industry's ability to provide a reliable supply of drinking water. Others are out there waiting their turn and, in every case, in every courtroom, when the gavel must come down on the side of water deliveries or a species at risk, the Endangered Species Act prevails.

So, rain or shine, bountiful rivers or cracked earth, we need to reduce our water use. We can't use twice as much as people in Europe do. And we can't use two-thirds of our available water on our landscapes.

I'm asking you to change that percentage. But I'm not asking you to change your lifestyle.

If you currently water your grass six days a week, cut it to four. If you water three days, reduce it to two. That's a 33 percent reduction, and if study's showing that we're currently putting twice as much water on our landscape as needed, you've still got a good cushion to work with. Then watch your lawn. If it begins to die, add a little more water.

But I think you'll be surprised at how it thrives.

Now I'd like you to do some math with me: If 70 percent of the water we use is outdoors, and we're able to reduce our outdoor watering by 33 percent, how much water are we actually saving? I'll give you the answer: 23 percent. With a painless tweak, you've already done your part to meet the state's goal, and you've done it with more than 11 years to spare.

Just think how much more you can save if you make a few more adjustments, like replacing a portion of your grass with a California-friendly garden.

National Drinking Water Week was May 4-10. In California, May is also Water Awareness Month. And, traditionally, May signals the onset of summer, a time when most homeowners decide to amp up their landscape irrigation.

This year, I encourage you to do the math.

— Al Yanez is operations manager of California American Water's Thousand Oaks District.