Hello Jalen,
Welcome to the forums! :qiime2:
Thanks for posting your full command and output files.
The first thing that jumped out to me was the small number of reads in your water sample.
It makes sense that sewage has fewer reads than tap water because sewage probably has more biomass than top water. (Hopefully! 
)
Low-biomass samples can be strange. With low biomass, low 16S copies, and low reads, it can hard to tell if a sample failed to sequence well, or if nothing was in it to start with!
Perhaps if the cohorts were balanced (5 sewage and 5 tap water), this would tell us more.