Subject: can other things be substituted for dH2O to prepare reagents

hi, need your advice in this scenario: if you're working in a criminalistic 
laboratory and need to prepare reagents using distill water for a rush-
rush project, but there aren't any at all on site, can you use tap water? and 
if not can you use anything else? of course with difficult question,  it's just 
reagents in general, no specifications at this point. by the way, i forgot if 
distill and deionized water are the same or not?!?  i would really appreciate 
your help.
 thanks a bunch!!!!!!!!!!!!!

Re: can other things be substituted for dH2O to prepare reagents