The formula, with its limits

WashDeal is a manual scenario worksheet. Its “Claim, Water, Questions” sequence is an interface organization, not proprietary science.

What is being compared?

A seller’s self-service washer receipt claim in USD and the receipts produced by an explicit set of assumptions for the exact same inclusive dates. WDF, dryer and other sales are excluded. No automatic annualization or period prorating is performed.

The arithmetic

1. Subtract wash-dry-fold, other non-wash and leak water from the measured volume. All deductions use the selected bill unit.
2. Convert adjusted water to US gallons.
3. Divide adjusted gallons by the sum of relative group total-cycle weights multiplied by each group’s gallons per cycle.
4. Multiply each group’s weight by that scale to get conditional total cycles. Multiply by its paid proportion to get paid cycles.
5. Multiply paid cycles by vend price and sum across groups. Compare those conditional receipts with the seller’s claim.

Weights are relative total cycles across a group. Inventory does not determine use. Income shares are not water shares. Unpaid cycles consume water but do not produce paid receipts.

Units and unknowns

One US gallon equals 3.785411784 litres; one cubic metre is 1,000 litres. A cubic foot is about 7.48051948 US gallons; CCF is 100 cubic feet. Per-cycle inputs always use US gallons. Imperial gallons are not supported.

Unknowns remain blank and prevent a numeric result. Assumed values can be entered with an explicit note, but the tool does not turn them into observed facts. A shared meter or dollar-only bill cannot support property-specific analysis here.

Why a match proves so little

The same water can come from different machine-use mixes, unpaid cycles or non-revenue use. A matching scenario is one possible explanation. It cannot authenticate financial records or distinguish misconduct from innocent differences.

Sources and what they do not establish

• Laundromat Resource: 3 Ways to Verify Laundromat Income. Discusses water analysis, its imprecision and a free spreadsheet. Its published prose is not a validated formula for this tool.
• Laundry Association: Best Practices for Due Diligence in Laundromat Acquisitions. Broader evidence-gathering context, not a certification of WashDeal.
• Dexter T-900 WCAD programming instructions. An example of model-specific programming documentation, not a universal gallons-per-cycle setting.

Source research was retrieved on 4 October 2026. No manufacturer defaults are preloaded. You must establish the relevant settings, use and evidence for your own scenario.

Try the counterexample

Use the synthetic example, save its snapshot, then change the small-group weight to 200 and the large-group weight to 400. The same water gives $2,400 rather than $2,100. A scenario range is not a confidence interval.