(FORTUNE Magazine) - Domestic robots: They're not just for geeks anymore. Here we are, just a half-decade into the 21st century, and already some 1.5 million iRobot (Research) Roomba floor-vacuuming machines are scooting around in houses like crazed, autonomous Frisbees, sweeping up dirt, fuzz, pet hair, and crumbs while their humanoid owners do more important things, like watch television.

But there are still some chores even more yucky than vacuuming, and still some places in the home where vacuuming alone won't make floors barefoot clean.

Scooba Floor Washing Robot -- $400

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I'm talking, of course, about mopping the kitchen and bathroom, or any hard floors where ickies and stickies happen. Once again, robots roll to the rescue. Like its older sibling the Roomba, the new Scooba Floor Washing Robot ($400, www.irobot.com) is not just a lazy person's substitute for the old bucket and mop; it's a superior cleaner. Instead of pushing dirty water around on the floor, as conventional mops do, the Scooba lays down a fresh coating of a special Clorox cleaning solution everywhere it goes. It scrubs the area with spinning brushes and sucks up the residual dirty liquid into its holding tank using a vacuum-assisted squeegee.

How it works: I tested the Scooba on my kitchen floor the day after it had been mopped by a professional housekeeper. It took Scooba about 35 minutes to traverse the standard-sized kitchen, zigzagging across open spaces, following walls, spinning in circles, and gently bumping off walls and objects, the same way the nonaquatic Roomba goes about vacuuming a room.

I'll spare you a detailed description of the foul water that Scooba vomited into the sink at the end of its cleaning cycle, but, yes, the silicon-based robot picked up more dirt and left the floor much cleaner than the carbon-based humanoid did.

Scooba is designed for sealed hard floors, and not for carpeting, plank floors, or other irregular surfaces. But in the interest of science, I also tested it on brick, saltillo tile, and wood floors with lots of grout or cracks. Scooba's inventor does not recommend using it on unsealed floors since the dirty water can seep into cracks or puddle where Scooba can't suck it up.

By the time the Scooba's cleaning tank (the reservoir that holds a double shot glass of Scooba Clorox and three cups of water) ran out of fluid on my brick bedroom floor, the dirty water tank held only a cup of sludge. Even so, despite the missing mess, the floor looked and smelled cleaner than it had for months.

The fine print: The Scooba has some design tweaks and extra sensors to compensate for the added complexity of mopping. Its touch-sensitive front bumper rides lower to the floor, enabling it to detect any transition between hard floor and carpet. If it detects a rise or fall of three millimeters, it backs off.

Scooba requires a special blend of robot-friendly, low-foam, non-corrosive Clorox cleaner that costs $18 for three 32-ounce bottles. Because each cleaning uses two ounces, it costs around 40 cents in supplies to clean a standard 200-square-foot floor.

Scooba's sensors prevented it from falling down stairs, and it had no trouble navigating common obstacles like table legs or low cabinets. It did get hung up several times on the brink of a foot-tall tile cliff, plaintively flashing the warning message I'M STUCK. (If it gets stuck, the pump shuts down automatically to prevent puddling.) Scooba comes with a fist-sized, battery-powered "virtual wall" that the user can position to keep it confined to a certain area.

On the downside, at nearly 15 inches wide, Scooba is not going to crawl behind the toilet or wiggle into recessed corners. It's slow by human standards. And I wish it had a laser-pen sensor so I could guide it to messy areas.

The bottom line: Our little robot friends are making the world a safer place for people who like to walk around the house barefoot. My spouse, who has banished other robots from the house, including Roboraptors, Sony Aibos, and remote-control cars, says Scooba may come live with us. That's the highest compliment Scooba can get.

Specs

Scooba Floor Washing Robot

Price: $400

www.irobot.com