This belief persists because water is visible in ways many other inputs are not. It moves through a tannery in plain sight, drawn from a source, used in a process, and discharged elsewhere. Compared with emissions or chemistry, it feels immediate and easier to follow as it moves through a site. Because it can be seen moving through a process, it is treated as a reliable signal of whether something is excessive or not. Spinoza would have recognised this instinct. When the mind encounters a strong image, it often mistakes it for understanding. The effect is taken as the cause, and the work of reason stops at the surface.

If the conversation pauses long enough to ask what actually happens inside modern tanneries, the picture becomes less dramatic and more precise. A decade or two ago, water use in leather processing was often high, not because the material demanded it, but because water itself was not closely managed. Rinses ran continuously. Equipment was designed for abundance rather than precision. Losses were tolerated because they were rarely measured in a way that made them visible or accountable.

Over the last decade, that approach has shifted markedly. Regulatory requirements tightened, discharge quality became more closely monitored, and water costs increased in many regions. Brands and auditors began requesting figures rather than assurances. As a result, water moved from being a background utility to a controlled input. Published benchmarks reflect this change. Where conventional practices once operated at water-use levels measured in several tens of cubic metres per tonne of raw hide processed, well-run facilities today report substantially lower figures. Best-practice ranges commonly cited in Europe now fall in the low tens rather than the high ones, with many sites operating at approximately half of what was once typical.

This reduction did not stem from a single innovation or technological leap. It came from accumulation. Shorter floats replaced deep baths. Batch washing replaced wasteful running water, and rinses were reused where quality allowed. Drums were designed to do the same work with less water inside them. Many tanneries have now transitioned to a closed-loop system. In this model, water is no longer a consumable resource but a circulating asset, captured, filtered, and returned to the start of the process. Metering moved from a single-site total to process-level measurement, making loss something that could be identified and corrected rather than assumed. Industry reporting in Europe over the last decade shows steady reductions in average water consumption per square metre of finished leather. This trend exists not because tanneries stopped using water, but because they stopped using it casually.

At this point, it is important to be precise about what water use actually means. In most modern tanneries, water is not consumed in the way fuel is. It is borrowed. It is taken from a source, used as a process medium, treated, and returned. In many regulated systems, the water leaving the site is cleaner and more controlled than when it was extracted. This distinction rarely features in public debate, yet it matters. The environmental question is not simply how much water passes through a facility, but what condition it is returned in and what pressures exist on the local basin. Quantity alone, without context, explains very little.

As the discussion continues, water use within the tannery is often conflated with water attributed to the entire livestock system upstream. Rainfall on pasture, irrigation of feed crops, and modelling assumptions about nutrient dilution are folded into a single figure described as leather’s water footprint. This kind of accounting has a purpose, but it answers a different question. It describes how water is distributed across a food production system that already exists. It does not describe what happens at the tannery gate, nor does it distinguish between water that falls as rain, water withdrawn from stressed basins, or water that is treated and returned under controlled conditions. The myth hardens when these distinctions disappear, and water becomes a single burden attached to leather itself rather than a set of flows that behave differently and respond to different interventions.

What is rarely acknowledged is that all manufactured materials contain water throughout their production processes. These processes for producing leather alternatives, vinyl and other coated textiles rely on water for polymerisation, cooling, washing, dispersion, and finishing. Chemical plants cannot operate without water, and surface coating and textile finishing processes are routinely water-intensive, even when the final material appears dry and uniform. In these cases, water use is simply less visible to the end user. It sits upstream in chemical production, energy generation, and material compounding. Because it does not pass through a drum in plain sight, it attracts less attention. The absence of an image is mistaken for the absence of water.

Spinoza’s point was never that understanding makes problems disappear. It was that understanding prevents us from responding to appearances alone. When water is examined with care, the story becomes less comfortable but more truthful. Tanneries use water, but they increasingly borrow it, manage it, clean it, and return it. Upstream water accounting describes a broader food system, not a decision made at the material specification stage. Alternative materials also rely on water-intensive processes, even when that water is hidden from view.

The myth dissolves not because water stops being used, but because it stops being misunderstood. Once causes replace impressions, the conversation becomes harder to sloganise and easier to address honestly. That is the light Spinoza had in mind.