Clare Davidson, BBC News
Port Sunlight, Merseyside
Unilever's Richard Craven shows Clare how to make a bottle of Small and Mighty
"For far too long, businesses like ours have been effectively shipping water around the globe," says Gavin Neath, a spokesperson for Unilever.
He leans across a table in the firm's London office, as if confiding something secretive.
Like other multinational firms, Unilever is assessing its environmental impact, including how it uses water.
In doing so the firm is reassessing the way it does business, but this also creates a number of benefits.
The firm singles out two detergents - Small and Mighty, and Surf Excel - as examples of this shift. Small and Mighty, for example, requires half as much water per bottle and half as much packaging.
Shift in size
As we arrive at the firm's Port Sunlight factory, near Liverpool, Keith Rutherford - who has been closely involved in developing small & mighty in the UK - has set up a display of detergents to illustrate the change.
Brands sold in different countries over the years are neatly arranged.
What would have been considered the norm now appear absurdly big in scale.
"In the past, especially in the US, big was always best," explains Mr Rutherford.
In the past, especially in the US, big was always best
Keith Rutherford, a director of Unilever's laundry R&D
"And the more bubbles and foam the better."
Making goods smaller challenges such assumptions.
As we enter liquid factory number one, we are hit by an intense waft of perfumed detergent.
As a robotic arm lifts bottles into a cardboard box, Mr Rutherford lists the benefits across the supply chain of making the detergent more concentrated.
Smaller bottles mean less packaging, meaning fewer carbon emissions.
"It also means more can be transported on fewer lorries which reduces fuel, which in turn lowers emissions.
"And making a more concentrated liquid means more goes further, so customers don't have to lug as much detergent from the supermarket as often."
As part of its overall environmental assessment, the firm has also looked at the consumer's role.
Litres per unit
Size of unit
Litres per kg
Sheet of paper
A4 sheet of 80gsm
Cup of tea
Cup of coffee
Bottle of beer
Slice of bread
Packet of sugar
Chunk of cheese
Packet of rice
Pair of jeans
This is effectively about looking at water used across the supply chain. While embedded carbon has been much talked about, embedded water, the water that is used in the life cycle of the product, has not. It is also called virtual water.
Water consumption at all stages is calculated; irrigation of the raw materials, the manufacturing process, water per consumer use, waste and greenhouse gas emissions.
"By looking at water we have an opportunity to look at the whole puzzle," says Mr Rutherford, gleefully.
A brief look at the firm's range of goods, from brands such as Knorr stock to Dove soap, underlines how important the end user's role is.
Plastic bottles of laundry detergent head down the production line
"It might be through boiling a kettle for tea, or making stock cubes or putting on the laundry", he lists.
Even pasta in tomato sauce needs water, albeit indirectly, since pasta needs to be boiled in water.
In fact, Unilever estimates that the water added by end users represents around 45% of the total water used for its products.
For detergent that figure is even greater - around 95% of the water is used by the consumer, mostly for rinsing.
"But you can't just abdicate that aspect, you need to raise awareness," says Mr Neath.
In countries such as India, washing clothes can represent around a quarter of the domestic water used and most water is used in the rinsing phase.
ENVIRONMENTAL SAVINGS SMALL & MIGHTY
Water: 41 million litres
Shelf space: 36 football fields
Carbon dioxide: 1 030 000 kg
Plastic: (equivalent) 272 million bags
Card: (equivalent) 383 million A4 sheets
Surf Excel Quick Wash, used in India, produces less lather, so the clothes need less rinsing, saving around two buckets of water per wash.
Some parts of the world where Unilever operates are water stressed, and many areas have no piped water.
Reducing the amount of water needed not only cuts the water required, it also means less physical work, with women and girls standing to benefit the most since they do most of the water carrying, said Mr Neath.
So reducing the water in goods not only stands to benefit the environment. It also has social implications.
Much has changed since the days of William Hesketh Lever, who co-founded the eponymous soap firm with his brother long before it was incorporated into Unilever.
But he might smile to think that aspects of his mission statement had been carried out.
"To make cleanliness commonplace; to lessen work for women; to foster health and contribute to personal attractiveness."
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