Damon Runyon, the author of Guys and Dolls, said mankind was divided into two kinds of people: deli guys and nondeli guys.

In my universe, humanity is also divided into two categories, but they are dishwasher people and handwashing people.

Then there is I, who both washes her dishes by hand and runs them through the dishwasher. But more about that later.

Studies show that washing dishes by hand uses three times as much water as washing them by machine. Any dishwasher made after 2013 is that much more efficient than manual labor.

Getting a full load clean by hand can use up to 27 gallons of water, while an Energy Star-certified machine can use as little as three gallons. This adds up to a savings of almost 5,000 gallons a year.

But what about all that glop that’s stuck onto plates after a meal? Can we believe the manufacturers’ claims that their machines will get it off?

“Yes!” says Santa Barbaran Andee Gaines, who studied up on this when she recently bought a new dishwasher and now considers herself an expert. “Everything comes right off except, for some reason, avocado.” (Another local resident said the same for peanut butter.)

How much does Gaines do to the dishes beforehand?

“A quick scrape and in they go,” she says.

I believe Gaines, but here’s why it’s hard for me to follow her example: Some years ago, I bestirred myself to make a brisket for a family occasion.

Cooked correctly, which is to say for hours, brisket should almost be falling apart by the time you serve it. That’s why, in order to pick up the pieces (which should be sliced on the diagonal, by the way), you have to use tongs. I did.

Then a family member, whose heart was in the right place but whose head was elsewhere, put the tongs in the dishwasher for me. As I was emptying the utensil basket later, the tongs were spanking clean, but a big wad of brisket was still stuck firmly in their grasp. I have pre-washed my dishes ever since.

Bob Vila, the home fix-it guy, says that if dishes are to be left in the dishwasher for more than a day, they probably should be run through the rinse cycle, which will still put you ahead of the game water-wise.

Most newer dishwashers can handle bits of food because there’s a filter somewhere inside the machine. I’ve yet to find it, although in all honesty I haven’t looked too hard. I really need to have more faith in technology …

Another reason to go with a dishwasher is that it heats up the water to 145 degrees, which sanitizes your plates and flatware. Your hands can’t handle such high temperature.

After reviewing all this evidence of water saving and china sanitizing, I vow to go through a 12-step program to wean myself off washing the dishes before I put them in the dishwasher.

And while I’m at it, I’m going to take down that picture of Lady Macbeth I have hanging over the sink. Upon reflection, she’s not a great role model. Anyone who cries, “Out, damn spot! Out, I say!” is obviously obsessive-compulsive.

Besides, she must have had a terrible case of “dishpan hands.”

— Santa Barbara author Barbara Greenleaf founded ECO Team to help repair the world, 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.