Human beings and bathing go back a long way together, from the Greeks’ sacred pools, to the Romans’ thermae, to the Japanese onsens, all the way up to today’s American hot tubs.

A favorite theme of artists, baths have always been about so much more than personal hygiene. They banish aches and pains, foster comforting rituals, lead to a better night’s sleep, and can even unlock creative ideas.

No wonder Aug. 15, National Relaxation Day, celebrates the bath.

Being a longtime bath lover myself (with a reading light installed over my tub), I’ve always felt a special affinity for Winston Churchill, who took very long, very hot baths, usually with a glass of Johnnie Walker Scotch within reach. From his command post in the tub, he made telephone calls, conferred with colleagues and dictated to his secretary, who sat just outside the bathroom with a portable typewriter on her lap.

I’ve also felt a special kinship with that other famous bather, Cleopatra, although her predilection for soaking in milk and honey makes me itch just thinking about it.

Contemporary big bathers include fashion designer Tom Ford, who reportedly takes three to five “power baths” a day, and actress Teri Hatcher, who pours red wine into her water, claiming its sediment is an excellent exfoliant. What a waste of good vino!

Milk, honey, wine — all well and good, but what can compare to the old-fashioned bubble bath, at least as depicted by Hollywood? It was what passed for risqué in the old days.

Who was that peeking up from the suds but Brigitte Bardot obviously not wearing a bathing suit, Agent 007 stirring a tub-side martini, and Groucho Marx fully clothed under the bubbles puffing on a big cigar.

Showers just don’t pack the same punch on the silver screen, except, of course, the immortal shower scene in Psycho. Haven’t seen it? Let’s just say it doesn’t end well.

Given the Southwest’s megadrought, Hollywood will have to find a substitute for the bath — and so will I.

The Colorado River, which supplies 60% of Southern California’s usable water, is running so low its pumps are becoming inoperable. Experts say it’s on a trajectory to run out altogether by the end of 2022.

Thanks to global warming, Sierra snowpacks, another very important source of water, are at risk of diminishing and melting before we need them most, in our dry summer months.

In Santa Barbara, Lake Cachuma is only at 48% of capacity, and the City of Santa Barbara is relying on desalinization to get us through.

When it comes to water, there really is no good news.

That’s why I am being propelled — albeit kicking and screaming — into the era of showers, and short showers, at that.

According to the Environmental Protection Agency, a full bathtub requires about 70 gallons of water, while a five-minute shower requires only10 to 25 gallons. I’ve put in a low-flow showerhead, too, because the EPA says that if every household installed one of these water-saving wonders, the United States could reduce its annual water consumption by 250 billion gallons and its annual water bill by $1.5 billion.

Saving water and money is such an unbeatable combination that I said goodbye to my old claw foot and sank it into the garden, where it is now home to dill, rosemary and mint plants.

Yes, I mourn the passing of the Golden Age of Bathing, but I mourn the passing of the Golden Age of Earth even more.

— Santa Barbara author Barbara Greenleaf has just started ECO Team so she’ll have company in her crusade to save the planet one paper bag at a time. For information, please email her at barbara@barbaragreenleaf.com. Click here for previous columns. The opinions expressed are her own.