How safe is Newmarket water really?

Another spring and, like clockwork, Newmarket's municipal water works is advising residents that another round of "swabbing" is needed to make our drinking water safe to drink again. (You can read about it here),

Swabbing is a process by which chemical agents are added into our drinking water to dissolve microorganisms, such as algae, molds, bacteria and other life forms, that accumulate on the pipes. While this process is underway, residents are asked to shut off the main water valve to their home for a period of 10 hours.

If your household needs water during this period, the township recommends filling a bath tub prior to the swabbing process and then using the saved water for washing, cooking, flushing toilets and so on.

Once the swabbing process is complete, the chemical will be flushed out through a neighbourhood fire hydrant to run off into the storm sewers or the local streams and water ways. If the town officials know how many hundreds of thousands of litres of water is being purged this way, they aren't making that number available to the public. Officially, they have told the public that they just don't know how much chemical laced water is being pumped into the environment through the fire hydrant.

Town residents are already familiar with the yellow-ish-brown discoloration in the water after swabbing occurs which the town assures is perfectly safe to drink. However, if you use the washing machine with discolored water, it will stain your clothes a yellowy-brown tinge.

I have found instances of other towns that will swab their drinking water system. I have never found another example of an Ontario town that does it annually like Newmarket does. Such a frequency begs the question if we can trust our Town when they insist our drinking water is as safe as other York Region municipalities?