When you buy a robot vacuum with a mopping feature, one of the first questions that pops up is: do I need to buy special cleaning solution, or can I just use tap water from my kitchen? It sounds like a simple question, but it actually affects how clean your floors get, how often you'll spend money restocking supplies, and whether your vacuum's mopping system stays healthy over time.
The good news: this is genuinely simpler than it sounds, and we're going to walk you through exactly what the difference is and whether spending extra on special solution is worth it for your situation.
So what actually is Cleaning solution vs plain water?
Your robot vacuum's water tank can be filled with two things: plain tap water from your kitchen sink, or commercially made cleaning solution designed specifically for robot vacuums. Plain water does the basic job of dampening your floors. Cleaning solution is water mixed with detergents and sometimes disinfectants — the same way you might add dish soap to your regular mop bucket, except it's pre-mixed and optimised for how robot vacuums work.
How does it work?
Think of it like washing your hair with just water versus using shampoo. Plain water will rinse your hair and get some dirt out, but shampoo actually breaks down oils and grime more effectively. With robot vacuums, plain water wets the mop pad and moves it across your floor, which picks up some dust and dirt. Cleaning solution does the same wetting job, but the detergents in it actually break down sticky residue, food splatters, and grime that plain water would just push around. Some solutions also have disinfectant, which kills bacteria on your floors.
Why does it matter for your home?
If you use only plain water, your floors will look slightly cleaner, but sticky messes — like juice drips or kitchen spills — won't disappear. You'll be pushing the mop pad over them without actually removing them. Over weeks and months, your mop pad can also get gunky and smelly because plain water doesn't have the cleaning power to really refresh it. With cleaning solution, you get genuinely cleaner floors, your mop pad stays fresher longer, and you'll feel more confident about hygiene in your home (especially in kitchens and bathrooms).
How does it compare to the alternative?
The alternative isn't really a different product — it's just using plain water instead. Some robot vacuum owners skip cleaning solution entirely and only use water, accepting that their floors won't be as clean. Others do a hybrid approach: plain water for daily passes, and cleaning solution maybe once a week for a deeper clean. There's no 'other brand' of solution to compare here — it's a choice between spending money on solution or saving money and accepting less cleaning power.
Do you actually need it?
Honest answer: it depends on your home and your standards. If you have a small, relatively clean flat with hardwood or tile, plain water might be fine — your robot is mainly keeping dust at bay between proper cleans. But if you have a kitchen, kids, or pets, cleaning solution makes a real difference. Sticky spills and pet paw prints actually get removed, not just smeared around. If you mop frequently (a few times a week), plain water might frustrate you because you'll see the same grime reappearing. If you mop once every two weeks, plain water is probably adequate for light maintenance.
Which robot vacuums have Cleaning solution vs plain water?
Have it
Don't have it
- ❌ Roborock S4 Max
- ❌ Ecovacs Deebot N8 Pro
The bottom line
Our take: if your robot vacuum has a mopping feature, buying the brand's recommended cleaning solution is a smart small investment. A bottle usually costs £5–15 and lasts several weeks. The difference in floor cleanliness is noticeable, and your mop pad will stay fresher. That said, if you're on a tight budget or your home is very clean to begin with, plain water works — you just won't get showroom-clean results. We recommend trying one bottle of the proper solution first, then deciding if it's worth it for you. Most people find it's a 'yes' once they see the difference.