Alot of Viruses or Bacteria remain dorment for some time before unleashing attacks, though for a very short time, these viruses are still spreading from one person to another though various orifice including the one behind into the sewer, and if they monitor the sewer they can catch something like this early in the group of population and hence a preventive measure before the next pandemic

Yes, the above was just in someone’s head during pandemic era

But then, they were able to also determine stress level in a given population with a study done in China from sewer water Link to paper in Pubmed

Your shit reflects what you eat, what you feel and underlying health conditions

For now, you are anonymous among the group of people living in the same town so they cannot exactly tell you apart from other’s sewer. But what if they find a way to shitprint where they can uniquely identify you from the shit you just dumped? Maby just a way to extract DNA from your shit stuff.

Maby if you are a wistleblower or someone the government would want to keep track of, they may somehow engineer a biological weapon that does not harm but will replicate itself just enough for it to be released from behind and let them know where you are.

Again, this is a far fetched and frankly stupid. But our current surveillance reality was just as stupid a decade ago.

I can imagine data brokers trying to get into the sewers to gather health data for advertisement far in the future. So I guess the only viable alternative would be to build septic tank to fight such surveillance like we currently do with selfhosting to protect our data. Just like we dont let these corporations get the hold of our data willingly, should we let our sewers get into their hand?