What troubles people is often not what ought to be troubling people.

Some of us might ignore a health problem until it becomes many health problems, or wallow in the end of a romance for so long as to miss our Main Chance as is steams past.

Though we all groaned as gas prices skyrocketed earlier this summer, we may have paid less heed to the upward creep of the price of a gallon of milk.

This year’s unpredictable presidential race, now entering the final, furious stage, has seen the focus pivot from the war in Iraq to the economy to — improbably — hockey moms. Who knows where the next bend in the road will lead us?

Meanwhile, state authorities tell us, something else going on under our noses is “the most significant crisis” of its kind in memory, where “dangerously unreliable” forces may have “potentially catastrophic” consequences for the economy and tens of millions of people.

That something is the drought, or more properly the state’s low water supply, in the words of the California Department of Water Resources.

DWR delivers water to many cities (including nearly all in Napa County), but is now inclined to spoon it out parsimoniously because the Sierra snowpack has been light for two years and because courts are enforcing laws that protect fish and wildlife, requiring humans to limit what they take from the Sacramento-San Joaquin Delta.

This being the arid west, what happens far away has effects, too. Way over yonder in the Colorado River basin, dry conditions have prevailed throughout this decade, with the exception of a single year. Seven states, including California and distant Wyoming, draw substantially from the Colorado River, the west’s mightiest and most heavily-tapped river, and one that is reduced to a relative trickle as it enters the Gulf of California.

Lawyers from these seven states have squabbled over this water since at least 1922, when the original Colorado River compact was signed, guaranteeing a supply to the states upriver and downriver of the Grand Canyon. Funny thing that you can guarantee water on paper, even if no one can guarantee it will fall from the sky.

Napa County is now playing the legal angles, though not over Colorado River water. County officials, seeing DWR offer up a too-meager portion of Sacramento-San Joaquin Delta water this year, recently sued the state. The theory is that we deserve special treatment because Napa County, via Putah Creek, supplies water to the delta while many other DWR clients do not.

Putah Creek tumbles from Cobb Mountain in Lake County, crosses into Napa — fed by a stream called Mysterious Creek, among others — then goes into Lake Berryessa and on through the rugged hills to the delta.

Old-timers shake their heads at the decades-old decision of Napa County not to tap Berryessa as a source for water, leaving it for Solano County. But that decision would appear to be behind us.

Other troubles would appear to be ahead.