When a wash bay, depot or maintenance yard changes its cleaning process, water is usually one of the first line items a manager asks about. Steam cleaning is often chosen because the high temperature, not a large volume of water, is doing the work. That difference changes the questions an operator needs to answer: what does a wash actually consume, where does the water go, and how do you prove the numbers when a site inspector, landlord or finance review asks for them.
Start with a metered trial, not a nameplate figure
Most machine datasheets do not publish an hourly water figure, and even when they do it describes a condition, not your duty cycle. The only number you can defend comes from one controlled run on your own fleet. A practical trial looks like this:
- Meter the water before it enters the machine. Where the machine feeds from a tap or a tank, a simple inline meter or a measured fill volume gives the same result. For an electrically fed high-pressure steam cleaning machine, record the tank volume, count how many times it is refilled during the run, and multiply.
- Record what you cleaned. Vehicles per hour, exterior surface area, whether engine bays, interiors or wheels were included, and whether staff pre-rinsed or pre-applied detergent.
- Log time, downtime and interruptions separately. A figure taken from a shift that included queueing is not a machine figure.
- Run the same vehicle mix twice, one cleaning day apart. A single day is never a baseline.
Write the inputs and the results on one page, keep that page, and let it become your site standard. Any later comparison — a new machine, a new crew, a new shift pattern — is measured against it.
Account for the water you do not see
Steam systems evaporate part of what they draw. So a measured figure has to be checked against the job actually completed rather than taken as pure waste. The comparison that matters to an operator is consumption per vehicle and per square metre of surface, not litres per hour. Build both into your log. Also decide what counts as water used: machine intake, manual rinsing, floor washing after the job, and bay cleaning after the vehicle leaves are frequently excluded from vendor claims but included in a utility bill. On a fixed installation fed from the mains, the bay meter will show them; on a mobile unit fed from a tank, they have to be written down.
Check what happens to the run-off
Low water use only becomes an environmental and compliance advantage if the run-off is controlled. Reduced volume makes containment and, where required, oil separation manageable; high volume makes it impractical. Before the trial, note what your site rules allow: whether wash water may reach the foul drain, whether it must be captured, and whether the surface being cleaned carries oil, grease or fuel residue. Engine-bay and depot-yard work is where this point most often decides the specification of the equipment, not the price of it.
Compare whole processes, not machines in isolation
Water is one input among several, and an assessment that stops at the litre figure will not support a purchasing decision. For each option on the shortlist, record the same set of items:
- Water consumed per vehicle, from the metered trial
- Labour minutes per vehicle, including setup and travel between bays — a driving-style or hand-pushed steam cleaning machine changes this, because the unit moves with the operative instead of the vehicle moving to a fixed point
- Power draw and the supply available on site, since a fixed 220 V unit and a battery-fed mobile unit have different installation requirements
- Chemical use, which high-temperature steam can reduce on greasy surfaces
- Disposal or treatment of the collected run-off
With those columns filled in, the decision usually becomes obvious, and it is usually not the machine with the lowest water figure that wins — it is the one whose total cost per cleaned vehicle holds up on your site.
Confirm the equipment matches the site
PowerDe's cleaning range covers fixed installations and mobile units, with dry-steam, wet-steam and hot-water modes across several models. Published parameters differ by model — tank volume, heating power, supply voltage and mobility — and the site itself notes that some wording and figures are not consistent across pages. Treat any specification as unconfirmed until it is verified with the manufacturer for the exact model and variant you are buying, including whether a battery is included. PowerDe describes customization and OEM/ODM support through its solutions page, which is the route to take when the site conditions, not the catalogue, drive the requirement.
Turn the trial into a standing record
Once the numbers exist, keep collecting them. A monthly line — vehicles cleaned, water consumed, run-off handled, labour hours — lets you show a trend, spot a leak or a process drift early, and answer an audit or a lease renewal without rebuilding the evidence from memory. Assessing water use is not a one-off exercise before a purchase; it is a small part of normal operation once the measurement habit is set.
