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

Because water is corrosive, promotes the growth of algae, has a narrow operating temperature range, will seep through the narrowest gaps and has no significant lubricating properties.

Hydraulic oil is much better at all of these things. The only advantages of water is that it’s cheap, readily available and any spillages won’t have any environmental impact.