Desalination has been inexpensive for 10+ years - ~$0.45/1000 liters (m^3) if you are willing to enter a long term (10+ year) contract. Down in Cabo, Hotels

Desalination has been inexpensive for 10+ years - ~$0.45/1000 liters (m^3) if you are willing to enter a long term (10+ year) contract. Down in Cabo, Hotels build their own desalination plants. The reason why you don't see broad adoption is that the competition is free, and often comes with gravity assist. The challenge with desalination isn't so much the cost of the product, but (A) its competition and (B) The ocean (almost) always has to be pumped up to get to its destination, which can be expensive (C) Pollution - you end up with a lot of byproducts that you need to dilute out into the ocean (and you still end up with pretty devastated areas of the ocean floor where it goes out). Cutting the price of desalination only helps with (A) - Even if desalination were completely free, you would still need to deal with geographic/pumping issues and the pollution.