(Wine-Searcher) - Water rights could make some vineyards worth 15 times more than their neighbors.

Some California vineyards will be worth a lot less money this week if, as expected, Gov. Jerry Brown signs a bill regulating groundwater use.

Previously, anyone – farmers or residents – could use as much water as they could pump from beneath their property. In the near future, local agencies will be able to say: "Hold it, that's enough."

The bill is not an impending apocalypse for grapegrowers by any means. Nobody would get their water rights cut off immediately, or possibly at all. But it would create a huge philosophical change in the ownership of groundwater in California.

Not surprisingly, some grapegrowers aren't happy. 

"The only people who are exempt from this are single-family homes," said Garrett Buckland, vice president of Napa Valley Grapegrowers. "It's a direct attack on agriculture."

It's too early to say exactly what the new regulations will require. Slightly different bills passed the state House and Senate, and Gov. Brown must sign both for either to take effect.

The bills were highly contentious in the Democrat-controlled state assembly, with most representatives from the state's parched Central Valley voting against them.