The amount of dissolved water in oil depends on viscosity and type of base oil, and additives. Some higher viscous oils (e.g., ISO 100 R&O turbine oils) were found to have saturation point from 500-750 ppm, ISO 68 from 150-250 ppm, ISO 46 from 80-120 ppm, and ISO 32 from 20-50 ppm. Additives can play a major role, too. For example, zinc-based additives tend to increase the amount of dissolved water in oil, as well as some EP additives. Whatever the level (below saturation point), dissolved water does not cause any significant problems, as free and emulsified water do. Therefore, one should be aware of the “comfort” level (ppms) of his/her oil, and not trying to beat oil to death through oil dehydrator trying to get to zero or below 5 ppm of moisture.