If you guys don't mind the labor intensive tasks of preparation, degreasing, hand polishing, etc., then by all means use whatever water you have. If you think the water doesn't make or break the blue job, you are in for an education. Costs very little extra to use distilled water or rain water. Screw up by using any old water and you'll have to do most of the preparation all over again. I learned the hard way. One experiment with tap water netted me about three hours re-do time. Just my 2CW. And I've blued dozens of guns with Pilkington's rust blue. Chopper
