Chemical-Free Floor Scrubbing: Electrically Converted Water, Evidence and Limits

Key takeaways

• Chemical-free scrubbing covers three different things: plain water scrubbing, onboard electrically converted or ionized water systems, and electrochemically activated solutions made from salt and water.
• Onboard systems can clean routine light to moderate soil on many floors while cutting chemical purchasing, residue and training errors.
• Much of the published performance data comes from manufacturers, and independent floor-specific studies are limited, so run your own pilot.
• Heavy grease, oils, protein soils and built-up residue still usually need a detergent or degreaser.
• These systems are for cleaning, not disinfection, unless a product carries a specific registered claim for that use.

Chemical-free floor scrubbing means cleaning with an auto scrubber that uses water, or water modified onboard by an electrical cell, instead of a detergent mixed into the solution tank. The best-known approach is electrically converted water (often marketed as ionized or electrolyzed water, with Tennant's ec-H2O as the most widely recognized example). These systems can handle routine light to moderate soil on many hard floors, but they are not a full replacement for detergents on greasy or heavily soiled floors.

The topic attracts both enthusiasm and skepticism, and both camps overstate their case. This page explains what the technologies actually do, what the evidence does and does not show, where they fit, and how to run a pilot that gives you an answer for your own floors.

Three different things called "chemical-free"

Keep these separate when reading marketing. A study about hypochlorous acid from an ECA generator says little about an onboard scrubber cell, and vice versa.

How onboard electrically converted water works

The principle described by manufacturers is broadly this: tap water from the solution tank flows through a cell containing electrodes. Applying a current causes electrolysis, which changes the water's properties for a short time. Depending on the design, manufacturers describe effects such as:

• Creating a mildly alkaline stream and a mildly acidic or oxidizing stream, then recombining them.
• Producing very small gas bubbles (often described as nanobubbles or microbubbles) that help lift soil from the surface.
• Changing surface tension or charge so water wets the floor and suspends soil more effectively.

Some systems also pass water through a conditioning cartridge, which manufacturers describe as reducing minerals that would otherwise interfere with the cell. Manufacturers generally state that the converted water reverts to ordinary water shortly after use, which is the basis for the claim that there is no residue.

What is reasonably well established: electrolysis changes water chemistry; dilute alkaline solutions help remove many everyday soils; removing detergent removes detergent residue; and most daily floor soil in many buildings is light enough that mechanical scrubbing with water does much of the work. What is less established: how much of the cleaning effect comes from the electrical treatment versus the brushes and water alone, and how large that difference is across real buildings.

What the evidence says, honestly

• Manufacturer data. The bulk of published performance data for onboard systems comes from the manufacturers or tests they commissioned. That does not make it wrong, but test conditions (soil type, floor, comparison product) are chosen by the seller.
• Independent studies. Peer-reviewed research specifically on onboard floor scrubber cells is limited. There is a broader independent literature on electrolyzed water and hypochlorous acid in food processing and healthcare, mostly about antimicrobial effects of controlled ECA solutions, which is a different product.
• Certifications. Some chemical-free scrubbing systems have received environmental or sustainability recognitions. Read what was certified: it is often the environmental profile, not cleaning efficacy against a detergent on your soil.
• Field experience. Operators commonly report that these systems work well on routine soil and less well on grease, and that results depend on keeping the cartridge and cell in good order.

The practical conclusion: treat chemical-free scrubbing as a promising option that must be validated on your floors, not as proven or disproven in general.

Where it fits and where it does not

Benefits beyond the chemical bill

• No over-dilution or under-dilution. Operators cannot glug concentrate into the tank. Residue complaints (tacky floors, faster re-soiling) often drop.
• Simpler training and fewer SDS sheets for the daily cleaning task.
• Less foam in the recovery tank, which protects the vacuum motor.
• Lower purchasing and storage of concentrate.
• Slip performance. Detergent residue can make some floors more slippery when wet. Removing residue can help, though slip resistance depends on the floor and its maintenance. If slip resistance is a concern, test with methods based on ANSI A326.3 rather than relying on claims; see slip resistance.

Limits and hidden costs

• Cell and cartridge upkeep. Cells and conditioning cartridges have rated lives and replacement costs. Ask the dealer for the rated hours or gallons, the replacement price, and what happens to performance as they age.
• Water quality. Very hard or very soft water can change performance. Ask whether your local water is within the system's specified range.
• Fallback to chemistry. Most buildings still keep a detergent or degreaser for problem areas. Check whether the machine allows switching to conventional chemical mode easily and whether doing so voids anything.
• Disinfection. Onboard systems are cleaning systems. Do not count them toward a disinfection protocol unless the specific product carries the appropriate regulatory registration and label claims for that use. CDC environmental cleaning guidance treats cleaning and disinfection as distinct steps.
• Higher machine price. The option typically adds to purchase cost. It must be paid back through chemical savings and labor or quality benefits.

Break-even: chemical savings vs system costs

Scrubber Guide model:

Annual chemical cost avoided = gallons of solution per year x chemical cost per gallon of solution

Annual system cost = (option premium / years of ownership) + annual cell and cartridge replacement cost

Worked example with stated assumptions: one walk-behind, two 20 gal tanks per night, 300 nights per year.

1. Solution per year: 2 x 20 x 300 = 12,000 gal.
2. Chemical cost per gallon of solution: concentrate price divided by gallons it makes. A concentrate used at 1:256 that costs C per gallon makes 256 gal of solution, so cost per solution gallon = C / 256. If C is about $25, that is about $0.10 per gallon of solution.
3. Annual chemical avoided: 12,000 x $0.10 = about $1,200 per year.
4. If the option premium is P and you own the machine 6 years, plus replacement parts R per year, break-even requires P / 6 + R to be less than about $1,200.

The example shows why the decision varies: a machine running one tank a night in a small building saves only a few hundred dollars per year in chemical, while a heavily used rider in a large facility saves much more. Fewer re-cleans due to residue, and less time training dilution, can add value, but estimate them conservatively. Your actual water and chemical use can be compared with water and chemical use benchmarks, and the broader economics fit into the ROI calculator.

A pilot protocol that gives a real answer

Run this for two to four weeks before buying a fleet or a costly option.

1. Pick two matched zones with the same floor type, traffic, and soil (for example two identical corridors or two aisles).
2. Reset both floors with a deep scrub so neither carries old residue.
3. Clean zone A with the chemical-free system and zone B with your standard detergent at the correct ratio, same machine class, same pads, same speed.
4. Measure weekly: white cloth wipe test in a marked spot, visual rating by a supervisor who does not know which zone is which, gloss meter reading if available, and complaints.
5. Check problem spots: entrances, food areas, under mats, around loading doors.
6. Record consumables: chemical used in zone B, and any cartridge or cell status indicators in zone A.
7. Decide with a rule set in advance. For example: adopt if zone A scores equal or better on cleanliness in at least 3 of 4 weeks, and no new slip or complaint issues.

If you have an ATP meter for hygiene auditing, it can add data, but remember ATP readings measure organic residue, not soil removal in general, and are mostly relevant in food and healthcare settings.

Questions to ask the dealer

• What exactly does the cell do, and what does the conditioning cartridge do?
• What are the rated life and replacement cost of each, and how will I know when they are worn?
• What independent testing exists, and under what soil and floor conditions?
• Can I switch to detergent mode for problem areas?
• What is your water hardness range, and does my water qualify?
• Can I have a demo machine for a two-week pilot?

More general dealer questions are on questions to ask a dealer. If you decide to stay with detergent, an onboard chemical dosing system captures many of the same residue and dilution benefits.

Frequently asked questions