How do we calculate the number of litres?
We’re often asked: “How do you actually calculate how many litres of clean drinking water you produce in your water projects?”
That is a good question and we are happy to answer it. Because at Made Blue Foundation everything revolves around transparency: we want to be able to deliver on every litre we promise, and preferably even more.
From tap to cubic meter
Our calculations start in practice. Imagine a public water supply with a borehole, a pump and ten taps.
In principle, a tap can fill a 20-litre jerry can 240 times a day – that’s 4,800 litres per tap per day.
But in reality, the pump sets the limit: it can deliver about 1,000 litres per hour.
Since people usually only collect water during the day – about 12 hours a day – the total capacity amounts to 12,000 litres per day. That’s about 600 jerry cans full of clean drinking water.
Assumptions per type of water supply
To ensure fair and comparable calculations, we also work with fixed assumptions for different types of facilities:
- Hand pumps: 20 litres per person per day.
- Schools: 5 litres per pupil per day.
- House connections: 60 litres per person per day.
These values have been deliberately chosen to be conservative – better to be a little too cautious than too optimistic. This way we can be sure that every reported liter is actually delivered.
A realistic lifespan
Then we look at the lifespan of the facilities. We calculate a project impact of 15 years as standard, in line with international guidelines.
An installation with the above-mentioned capacity can supply approximately 65 million litres of water in that period (12,000 litres × 365 days × 15 years).
Parts such as pumps or batteries need to be replaced periodically, usually after 5 to 10 years. We ensure that this is secured in the project plans.
Heavier components, such as pipes and concrete platforms, often last 20 to 30 years.
Count, compare and adjust
We continuously monitor which water supplies our projects have actually delivered upon completion. We use this to calculate the litres for the next 15 years, after which we deduct another 20% because something can always go wrong.
We add up all those litres to one big, global water balance. We always compare these with the number of liters we have promised to achieve to our donors. This way we can be sure that the figures are correct – and that every litre we communicate actually flows from a tap somewhere in the world.
Transparency as a starting point
For each project, we clarify which assumptions we use, which losses have been included, and what our figures are based on. This way, donors can trust that every litre in our reports is not just a calculation, but a real litre of clean drinking water, delivered to people who really need it.
An independent board oversees this, because transparency is central to Made Blue – from source to tap, and from litre to life.
Make litres of water available too
Convert the water you save, use, serve or sell with your company into the same number of litres of clean drinking water in developing countries.
This way, you make a tangible impact and increase your company’s meter reading. There’s more ways to support us than you might think.