eli5: If water is non-compressible, then why not use it in hydraulic machines instead of hydraulic oil?

Question

eli5: If water is non-compressible, then why not use it in hydraulic machines instead of hydraulic oil?

In: 1817

Answer 1

Water is compressible, otherwise the speed of sound in water would be infinite. It’s hard to compress water and the speed of sound is very high, but it’s not infinite.