If the quality of the tap water is that bad use RO water it's pure and all u need is some re-minerals and then u've got safe high quality water.
ammonia, nitrite, nitrate, PH, Hardnes(KH & GH), copper, iron, calciun are some of the things u can test for but who knows wot else u have in the water.
U can get RO water from ur LFS and if ur water isn't meaterd then u can get an RO unit.