Founder’s Letter: Water, Indigo and a Group Effort to Correct the Record
The Transformers Report on water usage in indog dyeing will be released on July 23
We all have heard the claim that it takes “1,500 liters of water to make a pair of jeans.” But do you know if it’s true? Well, it probably was back in 2020 if we based the number on outdated machines from 1990 with inefficient dye tanks used by low-quality factories that had no interest in saving water, energy or chemicals.
And yet, this 1,500-liter myth has been parroted so many times it’s become doctrine — it shows up in sustainability reports, IS featured in brand decks, and sometimes treated like gospel.
It’s not that people are lying. It’s that they never bothered to ask if this information is still accurate or look into the context. The danger here is that a lie that is repeated often enough could become a fact.
That’s why the Transformers Foundation looked into this to find out how much water is actually used in the denim dyeing process. The report (set to be released on July 23) is about yarn and yarn dyeing machines and indigo — and the gallons it takes to turn cotton yarn from white to blue.
It took seven mills, two machine manufacturers, and a small army of obsessive and time-generous textile scientists to put the report together. But what we found is simple:
The average post-dyeing water use is 13–15 liters per kilo for rope dyeing, 7–12 for slasher. With best practices? Under 4.
That’s it. That’s the real benchmark.
Financed by the Transformers Foundation and NDL by Naveena Denim, the report’s goal was to create an understanding for buyers to buy denim from those that really save water when dyeing and avoid the pretenders.
Now, if you’re still with me — and I hope you are — you might be asking why does this matter?
Because in 2024, the EU passed the Green Claims Directive. The UK has its Green Claims Code. The U.S. is knee-deep in lawsuits and state legislation is coming. You can no longer say “sustainable” without data. Claiming something is “environmentally friendly,” “climate neutral,” or “low-water use?” You better have verification. Transformers delivers this. Their study is your receipt.
Now, the reason we needed this study and why we need a benchmark is because without it, ambiguity is a gift.
Without this concrete data a brand could say their supplier “uses 80% less water” and nobody asks, “Less than what?” If you’re a mill, you just echo the brand’s claim and hope nobody audits your rinse boxes. And if you’re an equipment maker or a chemical company? This “savings” language could be used like seasoning — just enough to taste responsible, never enough to be specific. These savings mean nothing without specificity.
But the moment we introduce a benchmark — like 3.85 liters per kilo — you create accountability. Suddenly, 10 liters sounds excessive. Suddenly, that flashy new dye technology better prove it beats the standard. Suddenly, somebody in procurement has to read a technical sheet instead of an Instagram caption.
Transformers’s Indigo Report ends the ambiguity.
We chose to focus on pure indigo dyeing (no other dye stuffs) — not washing, not finishing — because this is an opaque section of denim. Chemical baths, oxidation timings, mystery rinses. Every mill does it a little differently. Which means every mill can claim their way is “better,”
The good news of this report is that the mills want the data public and were happy to share each other’s stats. Team work among competitors is an element and attitude that Kingins developed and Transformers utilized — and it makes me so proud of our supply chain.
After comparing rope and slasher, standard and best-case scenarios, across global denim leaders like Candiani, Orta, Soorty, Advance and Crescent Bahuman — we now have a reference point that’s solid and usable — and removes the reliance on half-truths and vague language.
And don’t get it twisted: this isn’t about picking a winner. It’s not the Olympics. There are generally two ways to dye indigo yarn. Rope dyeing is the dominant dyeing system and slasher, which is more flexible, and everyone knows that. Both have upsides, both have water sins.
Conclusions
- There is now an industry benchmark for water consumption in indigo dyeing:
- Rope dyeing: 13–15 L/kg on average, 3.85 L/kg best case
- Slasher dyeing: 7–12 L/kg on average, 3.4 L/kg best case
This essentially means if we substitute kgs of yarn for jeans we come to 1.7 liters/jean for rope or about 1.5 liters for slasher
2. Indigo efficiency matters.
Rope dyeing should yield 93–95% efficiency. Slasher, 85–94%. Anything below that means you’re wasting dye and water.
3. Liquid indigo (pre-reduced) is the future.
It reduces chemical use, water waste, sludge and operator hazard.
4. Slasher is the new wave.
It’s faster, cheaper, and — when well-run — can beat rope dyeing on water.
5. Modern machines + best practices = real savings.
One mill hit 3.4 L/kg without gimmicks — no “waterless” dye foam, no miracle startup tech. Just solid engineering and discipline. Transformers checked their data many times. We thought it was too good to be true but turns out it is and it’s fantastic.
6. Every denim buyer now has the right question to ask:
“How many liters per kilo?”
While this report focuses its entire effort on the water used to dye indigo yarn, the same study needs to be done to understand real usage of chemicals, and waste. None of us currently have real stats from the industry.
Further and finally we invite any brands or retailers who wish data to join us in supporting further studies. In this case, it took seven denim mills and two machinery companies to share information. Brands joining these studies would be helpful because like producers, they have a fundamental need for real data.
Our industry has gone a long way towards improving its environmental impact. And it can do more. We all need to realize we are rowing on the same boat. A better industry is possible.
Transformers full indigo report will be be available for download on July 23. Information will be available HERE.
For a deep dive into the report, the Transformers Foundation will host a webinar on Thursday, July 31st at 9AM Eastern Time (US and Canada). Registration is available HERE
