Having somewhat hard water, though depending on what makes up its hardness, can help in washing FB prints. If the water is high in carbonate, you may want to compare the residual thiosulfate levels, after washing in your hard water, and after washing in distilled water. You may be pleasantly surprised to find no difference, and maybe even better results with your well water. On the other hand, if your well water is heavy with some other less helpful minerals or heavy metals, you could be worse off with it, but I suspect you wouldn't have found it so tasty.
In any case, using a hypo clearing agent with FB should help no matter what water you use, being even more important when using distilled water.
Good tip. We actually live at the base of the Whetstone mountains (home of the famed Kartchner Caverns and likely many other caves.) So it is very likely that our water is quite high in carbonate. I never thought about it before, and just associated our water with horrible spotting on prints, and have been afraid to use it ever since. Maybe a wash in our well water with a final quick rinse in water with a wetting agent would work.
A small pack of FB paper and some more hypocheck will be on its way shortly!
New-ish convert to film.
Pentax MX for 35mm
Bronica ETRS for 645