Water tank

Large one-litre clean and dirty water tanks clip in and out with a reassuring click, reducing refill trips so users can tackle bigger or whole-house cleaning jobs more easily.

Class-leading tank capacity clearly wins in side-by-side tests, minimizing refills on whole-home or commercial-size jobs.

Reviewers find the fresh-water tank lasts for many cleaning cycles in average-size homes, with owners needing to refill only occasionally even with frequent mopping schedules.

The P10 Pro Ultra’s water tank is managed by the dock, which refills it automatically so the robot can handle long mopping jobs without manual refills.

The 880 milliliter clean water tank is larger than many rivals, so owners report fewer interruptions to refill during routine cleaning.

A dock-mounted clean and dirty water tank automatically feeds the S5X’s internal reservoir, with capacities large enough that most households only refill occasionally while adjusting wetness in the app.

Large clean and dirty water tanks with clear max lines are easy to remove, refill and empty, use plenty of water to wet floors and feed the self-cleaning cycle, and reduce how often users must walk back to the sink.

Slightly larger, flat-bottom clean-water tank is easy to fill and means fewer refills during routine sessions.

Separate clean and dirty water tanks keep fresh solution from mixing with collected grime, supporting more hygienic cleaning and reducing how often you need to refill in average-size spaces.

Large, easy lift tanks of about 4L for clean water and 3.4L for dirty water reduce the frequency of refills and emptying, and users appreciate how simply they lift out from the base to fill with tap water.

Much larger tank than the base TurboClean, meaning fewer refills when cleaning several rooms in one session.

Large solution and dirty-water tanks reduce refill and dump frequency for big spaces.

Large, easy-to-remove clean and dirty water tanks provide ample capacity and simple filling and emptying between sessions.

The P50 Pro Ultra’s water tank is automatically topped up from the dock between runs, enabling extended, multi-room mopping sessions where users usually only have to refill the clean tank and empty the dirty reservoir every few cycles.

Its dock-mounted clean and dirty water tanks feed an internal reservoir and recover waste water, and users can adjust wetness in the app while adding cleaning solution directly to the clean tank when desired.

Clean and dirty tanks lift out with hinged lids and fill lines for small vs large messes; reviewers cite roomy capacity for multiple stains (including ~0.2 gal clean fill line and ~0.5 gal dirty tank in one review) and easy pouring; tanks/tools should be rinsed and fully dried between uses, which can slow repeat sessions.

The bottom-mounted magnetic clean-water tank design is widely praised for stability and easier steering, with cited capacities around 0.79 L clean and 0.67 L dirty; the tradeoff is that some users describe the dirty tank as small and needing emptying mid-clean, and one owner mentioned minor dripping when setting the unit down.

Integrated water tank supports light mopping; water flow and low wetness are mentioned.

Clean and dirty water tanks handle mop supply and recovery automatically, so users rarely deal with dirty water directly, though the current opaque tanks rely on app notifications rather than a quick visual water level check.

Reviews describe the solution tank as easy to fill using the marked water and concentrate lines, and it clicks securely into place yet removes quickly for refilling at the sink, with enough capacity for a good-sized kitchen but sometimes needing a refill on very large expanses of flooring.

The system uses separate clean/dirty tanks in the dock plus onboard water management to keep the roller rinsed during cleaning; tanks are removable for rinsing, and early dirty-tank leak issues were reportedly corrected with updated parts.

Its generous dual-compartment water tank can cover a large area of hard flooring and keeps clean and dirty water separate, but because the WashG1 uses water aggressively for thorough washing, users still report having to stop frequently on deeper cleans to refill the clean tank and dump the dirty one.

Water tank capacity is enough for roughly 600–700 square feet of combined vacuuming and mopping before a refill is needed.

The clean and dirty water tanks are easy to fill, install, and empty, with clear max lines and a float that shuts suction off when the dirty tank is full.

Stretch S6’s tank capacities are comfortably sized for typical cleaning sessions and noticeably larger than Flexi Pro’s, so refills and emptying are needed less often.

Larger clean-water tank reduces how often you need to stop and refill during bigger cleaning sessions.

Uses a small internal water tank (often cited around 300 ml) suited to maintenance mopping; requires manual filling and pad prep, and can be limiting for larger homes or long mopping runs.

The clean and dirty water tanks are simple to lift out and rinse at the sink, though some owners wish they held a bit more water before needing to be refilled or emptied.

The clean tank is easy to fill and handle and, despite its smaller three-quarter-gallon capacity, typically covers around 100 square feet per fill and can even edge out some one-gallon rivals in passes per tank, though in real-world use reviewers still report needing at least one refill to finish an 8-by-10-foot rug or other larger spaces, while the dirty tank’s usable capacity is limited by a full sensor so it still needs periodic emptying on large jobs.

The separate clean and dirty water tanks are easy to fill to the marked lines and simple to remove and empty into the sink between cleaning sessions, though the dirty tank is small enough that some owners need to dump it at least twice when cleaning a large kitchen and reviewers note that it can reach the full line quickly despite the housing making it look larger.

Smaller clean water tank means more frequent refills compared with larger models.

The water tank is on the small side at 0.38 quarts, but efficient water use allows a full tank to cover roughly 700 to 800 square feet, making capacity feel adequate for typical quick cleans.

The clean and dirty water tanks are relatively small, making the Omni C20 best suited to smaller homes or more frequent refills, though they still support automatic mop pad washing between runs.

Water tank capacity is generally cited in the ~220–254ml range with adjustable water flow. Multiple reviewers note that the tank can run out during larger mopping jobs and that the app may not provide clear low-water alerts; refilling can interrupt or restart cleaning behavior.

Smaller clean-water tank than both the CrossWave and many cordless rivals means more frequent refills, but the trade-off helps keep the body lighter and easier to handle.

Small tank keeps the unit compact and light but requires more frequent refills if you clean more than a room or two at a time.

Smaller clean and dirty water tanks mean more frequent refills and emptying when cleaning larger areas, which some owners find inconvenient.

Small 0.2L water tank is easy to access but requires frequent refills during routine mopping.

The water tank is repeatedly described as small (around 180 mL), limiting mopping coverage and often requiring refills for larger areas. Some reviewers also note limited or no water-flow adjustment through the app.

Smaller clean and dirty water tanks mean more frequent refills and emptying during large cleaning sessions, a common complaint among owners.

Fresh-water tank and separate dirty-water reservoir work well for modest areas, but capacity is relatively small and may require refills for larger rooms or heavy-duty mopping.