How about going to the store and buying some distilled H2O, or better yet if you find yourself buying it stores all the time (who knows what you're doing) then go to Sears and buy a water distiller, they cost like $150.
Using distilled water for any extraction makes alot more sense, liquor stores around here sell 198 proof ethanol, which is alot better solvent then H2O for what you are doing.
If you are asking purely theoretically if Cl in tap water will damage extracted LSA, then the answere is probably to some degree.
If the only reason you don't have access to dH2O or other solvents is because you don't have any money, then maybe it's time to think about not doing it.
Also seperate from the original topic, using Hawiian Baby Woodrose seeds works alot better then using Morning Glory seeds, I guess it all depends on what the goal of your extraction is, and what the LSA is for. . .
Btw I wouldn't use tap water for anything, I don't even drink the stuff.
Cyril
So you need a precursor, to a precursor, just to make a precursor?