I don't use a water pre-soak, with one exception: MACO IR820. A pre-soak there is recommended by MACO to remove the anti-halation backing before processing. I use tap water.

Also, I have heard - I don't remember the source - that distilled water is not desirable in mixing developers, as some contain "sequestering agents" that - to some extent - "need" common impurities to "balance out" properly.

I have read advice by Ilford and Agfa against "pre-soaking" film ... that it lessens acutance and definition due to "swelling" of the emulsion before the developer has a chance to penterate and work its magic.

I have *NO* doubt that the last two remarks will spark a LOT of discussion.