(SonomaNews) - Local grape growers, especially those with a sustainability focus, haven’t just started paying attention to water use, says Steve Sangiacomo, one of two third-generation brothers (and a sister, Mia Pucci) running Sangiacomo Family Vineyards south of Sonoma.

“Sonoma County winegrowers have been leading the charge from an education standpoint,” he said, “doing a lot of education seminars even before the drought, to limit the use of water.”

The recent attention paid to the state’s diminishing water resources has focused attention on the high amount of water used in agriculture. Some claim that up to 80 percent of the state’s water is going to irrigate farmlands of one sort or another, though others point out that doesn’t include the half of the water in environmental use – that portion in lakes, rivers and streams not allocated for human use.

Since here in Sonoma County, most farmland is in wine production, which leads inevitably to questions about the amount of water we need to produce the county’s primary crop –and arguably, one of life’s great pleasures.

But estimates of water use in wine production range from 30 up to 150 gallons of water used to produce every glass of wine. A glass of wine is 6 ounces, a gallon is 128 ounces – so that’s roughly 7,000 times more ounces of water than you get in your pinot. It’s enough to make you turn your “Save Water, Drink Wine” T-shirt into rags.

Mike Sangiacomo points out that water conservation is not an add-on to traditional vineyard management practices, but “part of the viticulture process. How you’re going to prune it, how you’re going to manage the canopy, how you’re going to irrigate it.”

The 1,200 acres the family owns – most of it in the Sonoma Valley and Sonoma Carneros AVAs, though they also have vineyards near Petaluma and Penngrove – produce fruit for about 70 area wineries, including BR Cohn, Landmark, Ledson, Ram’s Gate and many more. They like the term “custom grape-growers” to describe their relationship with winemakers.

For all winegrowers, irrigation is a primary concern, but not just because of responsible water use. For years winemakers have known that the quality of the end product depends not only on how much water the fruit gets, but also on how little. A lack of water can increase the concentration of flavors in the fruit – while an abundance of water can make its flavors bland, even if production rises. “You want to make sure you’re giving the plant the right amount of water so it can focus on the development of flavors,” said Steve Sangiacomo.

Since grandfather Vittorio Sangiacomo started the vineyard in 1927, the technology of water management has changed considerably. There’s always been rainfall to serve as the primary water supply, and historic appropriated water rights from nearby streams – drawn in the winter months and used to fill reservoirs for use later in the year.

Now, however, a farmer’s instinct for how much water a vineyard needs is supplemented by new tools that accurately measure how much moisture is in the plant or the soil, and advise how much irrigation is needed for optimal growth.