Probably the worst thing about faucet water, is the chlorine or chlorime that is added to it. Both of these chemicals are deadly to aerobic bacteria and fungi in tea brewing. Chlorinated water can slow down microbial growth and organic matter decomposition in all composting methods.
One way to avoid this issue, is to use old stale faucet water, or let your water bubble in your bucket or tub for a few hours before applying your compost tea ingredients.
Some people use a little Tang (citrus acid) or hydrogen peroxide in their fresh faucet water in tea brewing to counteract the chlorinated water.
I keep a couple of 50 gallon rain barrels full at all times just for hot composting piles and aerated tea brewing. I sometimes toss a cup of urine or compost in the rain barrels to add extra nitrogen and microbes in the water.
Another lesser or minor issue of faucet water is pH. Based on where you live, some tap waters are too alkaline with calcium deposits. Most true rain water is slightly acid. Compost has a natural near neutral pH. Therefore simple compost leachates have a near neutral pH. Adding a few tblsp per 5 gallons of tea, of apple cider vinegar or citrus acid, is one way to get back to a slightly acidic pH that maximizes most natural foliar sprays, according to experts.
On the other hand, if you are like me, I use my aerated teas as both a foliar and soil drench all the time. Not just as a foliar spray. Since plants can tolerance good teas that have a pH from about 5.5 to 8.0, I don't bother about adding a natural acid to my teas for that reason. The available lime in my soil, and the beneficial soil microherd, take care of buffering the soil pH.
I have read that chlorine is easily diffused from faucet water after 24 hours anyway. That is why watering your organic lawn is not a big problem. The soil microbes quickly recover.
The entire Kingdom of God can be totally explained as an Organic Garden (Mark 4:26)