The saline water will harm plumbing, especially copper, brass or steel components. PVC or PEX would be best for corrosion, but you often have brass components with PEX. Washing machines would probably be harmed as well. I suspect the metal components in the washer would fail prematurely (solenoids, pumps components, etc.) It would probably also harm the water heater which consists mostly of metal components.
Determining how corrosive the water will be is somewhat difficult. You need more information on the water chemistry (and temperature). The commonly used calculations for determining how corrosive your water will be are the Langelier Saturation Index and Ryznar Stability Index. Both of these assume low chloride concentrations typically found in potable water systems. There are probably calculations for brackish water, I just have never used them or looked for them.