The Best Robot Mop I've Tested Is 30% Off Right Now (and It Vacuums Wonderfully, Too)

What's the deal?

The Eufy Omni S1 Pro is an outstanding robot vacuum and mop that keeps clean and dirty water separate, so it only mops with fresh water. It's currently on sale for $1,000, a $500 discount.

ZDNET's key takeaways

• The Eufy Omni S1 Pro robot vacuum and mop launched officially for $1,500, though currently discounted for $500. 
• This robot vacuum has it all, including great object avoidance and a mop roller that washes itself while cleaning your floors, ensuring only fresh water is used while mopping. This is by far the best mopping feature I've ever tested.
• The S1 Pro can be a bit loud when self-emptying, and the dock is taller than most.

Robot vacuum and mop combination devices seem to be getting better every day. Having previously used robot mops that drag a dirty microfiber cloth all over your floor, I used to find rotating mop pads innovative. But then came the self-cleaning robot mops with separate tanks for clean and dirty water, ensuring your floors are cleaned only with fresh water.

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The Eufy Omni S1 Pro has this kind of roller mop, and it's the most advanced robot vacuum and mop I've tested. It's the kind of device that truly has it all: strong 8,000Pa suction power with a rubber brush, a self-emptying charging station, a mopping roller that is continuously washed inside the robot while cleaning, a self-washing and drying station for the robot's mop, an LCD at the dock with touch buttons to help you choose a cleaning mode, and even an optional disinfecting system to ensure the mop stays free of bacteria.

Ultimately, a robot vacuum and mop combo is only as good as how well it cleans. You'll only spend $1,499 on such a device if you can be sure it'll pull its weight conveniently. But in almost three months of using it, I can say that the Eufy Omni S1 Pro is the most efficient robot vacuum and mop I've tested, both in vacuum and mopping mode. 

It's also by far the best mopping robot I've found. It could remove stains on my floors that my Eufy X9 Pro could not and proved to have better mapping capabilities than the Deebot X2 Omni is a competitor I've tested with similar features. It even mopped better than the best robot vacuum and mop I've tested, the Dreame X40 Ultra, only falling slightly short on its vacuum feature.

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It is a very efficient device; it uses less water per cleaning session than all my robots and cleans the same area in less time than most. While the Deebot X2 Omni cleans my downstairs in about 117 minutes, the S1 Pro does it in 70 minutes without missing a single spot. 

Until recently, the older Eufy X9 Pro was my favorite of all the robot vacuums I've tested; the only thing missing was a self-emptying dustbin. The S1 Pro improves on everything the Eufy X9 Pro could do, plus it has the self-emptying dustbin the older version lacked.

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The roller mop is about as wide as the robot vacuum unit and mops floors neatly without leaving streaks or tire tracks. It only mops with clean water, as the robot continuously scrubs the mop roller clean while moving about your home. I was skeptical of this system when I first saw it on the Switchbot S10 robot vacuum and mop. It seems like anything could get stuck in it, or the roller itself would wear down with regular use, but this hasn't been the case.

Aside from some extra periodic maintenance compared to other robot vacuum and mop combos, the Eufy Omni S1 Pro's mopping feature has performed flawlessly over the past three months. The roller mop system that only uses clean water to wash floors requires a feat of engineering packed into a small unit, which includes a dirty water tank with many moving parts and removable pieces. 

This dirty water tank, or "sink," as Eufy calls it, can get clogged if not cleaned periodically. It only requires a deep cleaning about once every other week, which is still much more convenient than mop your floors manually. And it evens out when you consider that you won't have to refill the water tank as often as other 2-in-1 robots because the S1 Pro is so efficient.

Also: The best robot vacuums for pet hair: Expert tested

The dock's touchscreen LCD is also a useful feature. It lets you change from vacuum to mop mode from the base station, which you'd have to do on the app with other models. I also appreciate the ability to call the robot back to charge whenever possible.

But where does the Eufy S1 Pro go wrong?

For starters, it's very loud. The robot is quieter than the older X9 Pro and the Deebot X2 Omni on hard floors, though it can get loud when the suction power is turned up. In addition, the charging station is very noisy.

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The first time the robot docked itself to vacuum up the contents of its dustbin, it sounded like it was about to take off into orbit. My toddler wandered into the room where the S1 Pro was to ask it if it was okay. The machine then responded by beginning the very loud process of washing its mop pad, which consists of a series of regurgitating sounds that would have made the other self-washing robot mops in my house clutch their pearls.

I can live with loud - I have three young kids, after all -- but it is inconvenient knowing that you can't run it at night because your kids would wake up thinking a plane is landing on the driveway. You can set 'do not disturb' hours so the robot doesn't perform self-cleaning tasks during a determined time of day.

The charging station is also very tall. For comparison, the Eufy X9 Pro is about 17.5 inches tall, the Deebot X2 Omni station is 20.5," and the S1 Pro is 26.75" tall. It looks sleek and modern, but it also sticks out.

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The only other thing I'm not a huge fan of is what Anker calls the Eco-Clean Ozone and I was glad to see it's an optional setting. This has the machine produce ozonated water from tap water, which is used to deep clean surfaces and kill bacteria. 

Ozone is a very effective disinfectant; it quickly neutralizes bacteria, viruses, and fungi in seconds. However, ozone in gas form is also a known lung irritant, so I strongly discourage people from buying ozone air purifiers or having a device that uses ozone gas in their homes. I was recently diagnosed with a genetic illness that puts me at risk of fatal lung disease, so I can't chance having a device that could harm me, no matter how well it cleans.

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I reached out to Anker to inquire about the safety of the production of ozonated water by the S1 Pro, and the company shared a 600-page report from the TUV Rheinland laboratory. This testing was performed based on the IEC and UL standards, and the S1 Pro passed the "Radiation, toxicity, and similar hazards" clause, which includes ozone production. The highest amount of ozone measured during testing was 0.67 parts per million (ppm), which is well within the safety zone of the IEC standard of 5 ppm, making it harmless to human health. 

Of course, I still decided to test the Eufy S1 Pro, ozone and all, but after the first cleaning, I toggled off the Eco-Clean Ozone feature in the Mach app. As an overly cautious person, I appreciate that you can turn it on or off.

ZDNET's buying advice

Based on performance, the Eufy Omni S1 Pro seems to be worth every single dollar of the $1,500 it costs. This robot vacuum and mop does it all and does it well. It mops almost as well as I do, actually cleaning my floors with clean water in each pass rather than dragging a dirty pad all over. 

Watching the S1 Pro gracefully glide around my house, picking up every strand of pet hair and, for the most part, not getting tangled in socks, stuff my kids left behind, or cables had me brimming with excitement. It's one of the top two robots I've tested with reliably great obstacle avoidance, topped only by the $1,900 Dreame X40 Ultra.

Also: 6 things to know about robot vacuums before you buy one

This is the best if you want an efficient yet effective high-end robot vacuum that can auto-clean itself. But suppose you want a vacuum that can fully operate during quiet hours and won't emit any potential irritants (though you can always turn off Eco-Clean Ozone). In that case, I'd advise you to check out one of ZDNET's other tested vacuum and mop combos.