Today, we’re taking an in-depth look at two of the most advanced robot vacuum mop combos on the market: the Roborock S8 MaxV Ultra and the Dreame X40 Master. Both of these “plumbots” feature plumbing-integrated water refill and drainage systems. This eliminates the need to refill clean water tanks or empty dirty water tanks, and ultimately brings us closer to fully automated floor care. We purchased both models and have extensively evaluated them over the past few weeks.
Let’s dive into the results and see which one came out on top.
Dreame X40 Master
Vacuum Wars Stars 3.57
The Dreame X40 Master is a high-end robot vacuum and mop built around an 8-in-1 base station that can connect directly to a home’s plumbing for automatic clean-water refilling and wastewater drainage. The compact 11-inch-tall dock also handles debris emptying, hot-water mop washing, heated-air drying, self-cleaning, and dirty-water monitoring. The robot combines a claimed 12,000Pa of suction with an extending side brush and mop pad, liftable and removable mop pads, carpet boost, and 22mm threshold crossing. A camera, 3D structured light, and spinning LiDAR support obstacle avoidance and navigation, with recognition of up to 120 object types. In Vacuum Wars studio evaluations, navigation efficiency and battery life were particular strengths. The app adds multi-level maps, virtual barriers, no-go zones, live video, and pet checkups. See additional info
Roborock S8 MaxV Ultra Refill and Drainage
Vacuum Wars Stars 3.18
The Roborock S8 MaxV Ultra Refill and Drainage is an advanced robot vacuum and mop paired with a RockDock Ultra that connects to household plumbing for automatic clean-water refilling and wastewater drainage. The dock also empties the robot’s dustbin, washes the mop with hot water, dries it with heated air, dispenses detergent, monitors dirty water, and cleans itself to reduce routine maintenance. The robot combines a claimed 10,000Pa of suction with VibraRise 3.0 dual lifting mop pads, an extending mop section, a FlexiArm extending side brush, carpet boost, and 20mm threshold crossing. PreciSense LiDAR, a front camera, and 3D structured light support navigation and Reactive 3D obstacle avoidance with recognition of up to 73 object types. The app includes multi-level maps, virtual barriers, no-go zones, voice-assistant controls, live video, pet checkups, and video calling. See additional info
Hardware and Suction
The Dreame X40 Master uses a single roller while the Roborock features a dual brush roller system. Both have automatically extending side brushes, which we found to actually improve corner coverage.
In terms of suction power, the Dreame X40 Master leads with 12,000 Pascals compared to the Roborock’s 10,000 Pascals. So it was no surprise in our suction and airflow evaluation that the Dreame X40 offers more raw power.
Vacuuming
When cleaning hard floors and carpets, both models excelled in picking up various sizes of debris without any issues.
However, in our Carpet Deep Clean evaluation, which we evaluate by embedding sand in carpets and weighing their dustbins after a timed run, the Dreame outperformed the Roborock, removing more embedded sand.
Additionally, Dreame’s single roller resisted pet hair tangles better than Roborock’s dual rollers, with only 26% of hair caught compared to Roborock’s 59%.
Mopping Features and Performance
These robot vacuums use different hardware to mop floors: The Roborock uses VibraRise technology with a vibrating single mop pad, while the Dreame employs dual spinning mop pads.
Both robot vacuums also have edge-mopping capabilities, but only Dreame’s mop pads extend. The Dreame’s auto-extending mop pad provided better coverage, even reaching under doors and furniture.
Both models also allow water dispensing control via their apps.
In our dried-on stain evaluations, the Dreame slightly edged out the Roborock, scoring 92 versus 88, although with the margin of error, those scores might as well be a tie.
What really sets these mopping systems apart are their fully featured charging docks. Both mopping systems have charging docks that handle nearly every aspect of cleaning and maintenance:
- Recharge the robots
- Empty the dustbins into a disposable bag
- Automatically wash and dry mop pads
- Refill onboard water tanks
- Use hot water to wash pads and hot air to dry them
- Dirty water sensors with self-cleaning options
Plumbing Integration
Compared to most robot vacuums, the primary distinction between these two models is that they both feature tubing and plumbing connections, allowing you to connect them to your home’s plumbing system. They both come with a remarkably similar three-way diverter valve and roughly the same amount of tubing, so there wasn’t much difference in terms of what was included.
There are many ways to connect these to your home’s plumbing, but the simplest option is to place them near a sink or toilet. Alternatively, you could build a custom cabinet or similar enclosure. While the installation is relatively straightforward, having some basic plumbing know-how is helpful. So if you’re unsure, it’s best to ask someone handy for assistance.
Dock Size Differences
Another important note is that the Dreame’s dock is slightly longer than the Roborock’s dock. And depending on where you want it placed, it can easily stick out too far if not built into a custom cabinet or a similar structure. The Roborock dock is shorter and taller, and would fit well just against a wall.
Obstacle Avoidance
Both have front-mounted obstacle avoidance cameras and structured light sensors to recognize and avoid objects. While the Roborock got a respectable, average score in our obstacle avoidance evaluations, the Dreame was significantly better, earning one of the highest scores we’ve seen.
The Dreame has also been programmed to recognize a higher number of objects—120, compared to only 73 on the Roborock. If obstacle avoidance is important to you, the Dreame X40 Master is definitely better.
| Roborock S8 MaxV Ultra | Dreame X40 Ultra | Average Robot Vacuum Tested at Vacuum Wars | |
| Obstacle Avoidance Score | 16 | 22 | 17 |
| Objects Recognized | 73 | 120 | N/A |
How Vacuum Wars Tests Robot Vacuums: Step into the world of Vacuum Wars, where real-world tests, straight-forward reviews, and no sponsored products redefine robot vacuum evaluations.
Battery Life
We found the Dreame X40 Master to have better battery life overall, despite having similar official numbers on low power. In our evaluations, which we run on all power settings, the X40 Master was more efficient and had a much higher square-foot-per-charge estimation. While both of their battery scores were above average, the Dreame X40 was better.
Battery Scores
| Roborock S8 MaxV Ultra | Dreame X40 Ultra | Average Robot Vacuum Tested at Vacuum Wars | |
| Official Battery Life Minutes (Low Power) | 180 | 189 | 154 |
| Battery Efficiency Minutes per % | 1.66 | 3.44 | 1.36 |
| Square Foot Per Charge (Estimated) | 1489 | 2591 | 1007 |
Navigation
Both robot vacuums navigate the house in a similar way, using a top-mounted LiDAR sensor. They both feature multi-level mapping and fast mapping, and in our navigation and coverage evaluations, they demonstrated an amazing ability to efficiently cover the space without getting stuck. However, the Dreame X40 Master ultimately achieved a higher navigation score.
Apps and Software
Both brands have what we consider some of the best apps in the business, with seemingly every possible advanced software feature you can find on a robot vacuum. Plus, they both maintain excellent app ratings on the app stores.
The main difference between the apps is that the Dreame doesn’t have a built-in virtual voice assistant, whereas the Roborock does. However, the Dreame can still be used with Amazon Alexa and similar devices.
Final Verdict: Which one is better?
After adding up all the scores, the Dreame X40 Master (Amazon Link) beat out the Roborock S8 MaxV Ultra (Amazon Link) by a significant margin. However, both of their final Vacuum Wars scores were above average. As of the time of writing, the Dreame X40 Master is currently ranking #4 on our Vacuum Wars Top 20 list with 4.5 stars, while the Roborock S8 MaxV Ultra is in 11th place with 4 stars.
Update 1/27/25: The Dreame X40 Master is currently ranking 2nd with 4.7 stars, while the Roborock S8 MaxV Ultra is now 8th with 4.4 stars.
Compare the Dreame X40 Master
See how the Dreame X40 Master compares to similar robot vacuums. Select a model to view the full comparison. You can also compare additional models using our robot vacuum comparison tool.
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