Bitcoin mining annual water use
TLDR
Each Bitcoin sub transaction requires 0.05L or 1/2 🥃 & 0.4 kWh of electricity.
The average $100,000 onchain transaction requires 1/2 a Bucket of water 🪣 & Tesla battery of electricity.
The average $100,000 onchain transaction requires 1/2 a Bucket of water 🪣 & Tesla battery of electricity.
In November 2023 Alex de Vries & the BBC claimed 
"In total, bitcoin consumed nearly 1,600 billion litres  also known as gigalitres (GL)  of water in 2021" Every Bitcoin payment 'uses a swimming pool of water" (see screen shot). This seemed a little excessive, because in my own experience of home mining I do not use ANY water what so ever !? What do they mean by use ? evaporation ? cooling circuit ? So I decided to calculate both. Thought experiment 
If we took the most extreme power estimate (also Alex de Vries 🤔 ) to see how much water we could boil. This would give the absolute maximum amount of water that could be lost via evaporation.
Basics science tells us we need 2256kJoules or 1.596kWh to evaporate 1 litre or 1kg of water. In 2021 Bitcoin power consumption was around 50 400 TWh/year depending on the estimate ( My calculations show 56TWh ), we will take the worst case scenario 

(no link because I do not want to back link to rubbish thereby lending page ranking "authority" . So you'll just have to find it yourself.)

Litres water = Power / Latent heat of vaporization
= 400,000,000,000 kWh / 1.596 kWh
= 250,000,000,000 Litres ✅ or 100,000 Olympic Swimming pools
not 1,600,000,000,000 Litres ❌ or 640,000 Olympic Swimming pools
= 400,000,000,000 kWh / 1.596 kWh
= 250,000,000,000 Litres ✅ or 100,000 Olympic Swimming pools
not 1,600,000,000,000 Litres ❌ or 640,000 Olympic Swimming pools
So there we have it, actual mathematical proof Alex de Vries & the BBC are wrong !
Misinformation !
Misinformation !
Current Bitcoin mining water use 2024
Roughly only 21% of ASIC's are or were water cooled, of that 21% an estimated 30% dissipate heat via evaporation. Everything else is air cooled. The coolant loop, like your car may have its water changed once a year. We will assume 2 Litres of water per ASIC for the cooling loop.

Although figures are not exact, they are not wrong by > 2 orders of magnitude especially if we take into account mining would be consuming half the amount of electricity in 2021 compared to current values.
Litres per transaction
4,343,552,909 per year / 365 = 11,900,145 Litres per day
Litres per TX = Litres per day / Transactions per day
11,900,145 / 330,000 = 4.3 Litres per transaction
A very small "swimming pool" 🤔 actually more like half a bucket 🪣 . Not bad for sending an average TX value of $100,000 across the world.
Litres per TX = Litres per day / Transactions per day
11,900,145 / 330,000 = 4.3 Litres per transaction
A very small "swimming pool" 🤔 actually more like half a bucket 🪣 . Not bad for sending an average TX value of $100,000 across the world.
Adding more detail
Mining energy serves 2 main purposes  Block reward (like mining gold) and Transaction Fee's (like spending gold). We never think of all the water used to mine gold when we spend gold. So we'll similarly discount it here for a fair comparison.
Now for 2024 we have to factor in not only straight forward onchain TX's but also Lightning & Batched payments that are really taking off. Let's say on average for every onchain transaction there are 100 Lightning or Batched transactions.
2.4 Litres / 50 = 0.05 Litres per Transaction or 0.08 Pints 🍺 or half a dram 🥃 Cheers !
2.4 Litres / 50 = 0.05 Litres per Transaction or 0.08 Pints 🍺 or half a dram 🥃 Cheers !