Drinking Tap Water

Depending on where you live and the water system in your house, you water can contain, chlorine, fluoride, minerals natural to the reservoir you water comes from, lead and copper from soldered copper pipes and any number of pollutants get into you water system. City water works only have to make the water fit to drink as far as bacteria count is concerned and chlorine is used to kill bacteria int he water. Another chemical is used to remove the chlorine but it does not remove all of it because, depending on the time of year and you water source, the water has to be saturated with chlorine to kill bacteria from run off from rain or snow. To have pure water from a city system you need a good filtration system and black light to kill all the bacteria.
Spring water on the other hand is naturally filtered water out of the grounds water table and is not usually surface water like most cities have. However, again depending on where you live and the industry in the area, spring water can be just as bad as surface water.
My suggestion is to have your water tested and determine for yourself if the stuff in the water is worthing putting into your body. If that is too much work then get water from a reverse osmosis system like Culligan but be aware the good minerals in water that your body needs are also removed with the RO system so that water is basically hydration and does not supply precious minerals your body usually gets from water.