When a factory audits its water use, the production process gets all the attention. Cleaning the machines that make up that process is usually measured in hours spent with a hose, not in litres. That gap makes it hard to tell whether a change in cleaning method would actually save water, or money. The evaluation itself is simple: measure what you use today, define what "clean" requires, compare methods on the same basis, and verify with a short trial.
Step 1: Measure what cleaning costs you today
Few plants have a meter on the wash-down line, so the first number has to be created. Two practical ways to get it:
- Read the water meter before and after a scheduled cleaning shift, or fit a temporary inline meter on the wash-down supply.
- Where metering is not possible, time each hose in use and multiply by its flow rate. A factory hose delivers several litres per minute, so a twenty-minute wash-down adds up quickly once it is repeated across machines and shifts.
Record the indirect uses as well: pre-rinses, water used to mix and rinse detergents, and the floor wash-down that follows machine cleaning. In many plants these exceed the machine wash itself. Log the figures per machine and per event, because a plant-wide average hides the one line that accounts for most of the consumption.
Step 2: Define what "clean" actually requires
Water use follows the soil, not a supervisor's personal standard of tidiness. Before comparing methods, write down what has to be removed from each machine: cutting oil and coolant residue on machine-tool surfaces, grease on drives and gearboxes, swarf and dust inside enclosures.
The soil type decides the method. In production line equipment degreasing, heavy oil and grease are the cases where cold water and detergent need the largest rinse volume, because heat, not extra water, is what releases viscous soil from steel. Set the acceptance standard in advance: visible soil removed, no residue on a wiped surface, no oil carried onto the floor. A fixed standard is the only way different methods can later be judged on the same result.
Step 3: Compare methods on litres per cleaned machine
Ask every supplier to quote in litres per machine or per square metre, not per hour, and compare the common options on that basis:
- Cloth and bucket: the least water and the most labour, with little effect on hardened grease.
- Hose and brush: flexible, but the water runs whether or not soil is coming off.
- Pressure washer: pressure replaces volume, so consumption drops sharply against an open hose; hot-water models cut grease faster and shorten the rinse.
- Steam: the water is held in an onboard tank and converted to vapour, and dry steam carries very little free water, so a small tank supports a long session. PowerDe's industrial steam cleaning equipment includes fixed 220 V units such as the HW02, with a 6 kW heater, an 80-litre stainless steel tank, and steam at 160 °C and 0.8 MPa, figures a factory can put straight into a per-cycle water budget. Confirm the configuration and duty cycle with the manufacturer before specifying a unit for your line.
Step 4: Count the indirect water costs
- Wastewater treatment: oily rinse water normally passes an oil separator or on-site pretreatment. Lower volume with a higher soil load can reduce treatment cost, but check your discharge limits before changing the method.
- Chemicals: hot water and steam often reduce or replace detergent, which also removes the rinse water needed to flush chemical residue off the machine.
- Restart time: wet floors and standing water delay start-up after maintenance. Low-moisture steam leaves surfaces nearly dry, which shortens the restart and reduces the slip hazard.
Step 5: Run a controlled pilot before deciding
Pick one machine and one recurring task. Clean it two or three times with the current method, logging water, crew hours, and elapsed time. Repeat with the candidate method under the same acceptance standard. Compare litres per cleaned machine against labour hours and pass rate; a method that uses less water but fails the standard is not a saving. Keep the log, because it is the evidence you will need for the EHS review, the water authority, or the capital request.
From habit to a number you can manage
The purpose of the evaluation is not to prove that steam or hot water always wins. It is to replace "it takes two hours with the hose" with a figure you can manage. Once water per cleaning event is measured, low-water steam cleaning equipment becomes a procurement decision you can justify with your own data rather than a supplier's slogan.
