California’s water wars stretch back decades and decades, but the signs that conflict is increasing are abundant.

One obvious sign is the lawsuit that Napa County and two other counties filed last month. The theory of that lawsuit is that those counties and cities with streams that flow to the Sacramento River and the Delta — which slakes the thirst of much of the state — deserve better treatment at the state Department of Water Resources than the many counties that don’t.

The suit comes after Napa County saw a cut of nearly two-thirds in its state water allocation this year. The county has standing to seek better treatment, the suit argues, because Putah Creek flows from the shoulders of Mount St. Helena to Lake Berryessa, where it drops through the Glory Hole and on to the Delta.

It is too early to say whether Napa County and its cohorts have the law on their side. But the politics are not very favorable. Southern California counties that are heavy water users may battle for every drop.

A drop-by-drop battle, that’s how things are shaping up in California after a couple of dry years, a steady trend toward population growth and a look at projected models for how climate change might affect California.

There are some favorable changes out there. For example, Napa and many other cities are using the same amount or less water per capita than they did years ago, when their populations were much smaller, because people are using water-saving devices and practices in their gardens and homes. Orange County, in Southern California, has invested billions in a wastewater recycling system.

Yet trouble is brewing on many fronts. The pressure on the Delta comes from many sides: Municipal users, agricultural users, fish and wildlife and their advocates among humans, problems caused by toxic runoff. In addition, the health of San Francisco and San Pablo bays are largely dependent on the health of the Delta.

Lawsuits between government agencies over complex issues like water allocations have a tendency to drag on forever.

It is our hope that the Department of Water Resources sees the importance — and minimal harm — of upping the supply to the affected agencies and eases the pressure without marathon litigation.

But when the lawsuit is over, it’s a sure bet that California’s water wars will still be raging.