Ok I'll bite, WHY?
Besides, if you could see what’s on the inside of your area’s water supply pipes, oil would be the least thing you would worry about.
So what's in our city water mains?
I use to install water mains, when connecting a new line to the main we used a core cutter made by “Mueller.” The cut into the side of the pipe is taken to a state lab and analyzed in order to determine the amount of pipe “tuberculosis.” Along with all the minerals that are in water every sort of microbe you can think of resides in it along with whatever makes it into it from soil run-off (fertilizer etc...) carcasses from anything that frequents the water supply. The tuberculosis has been diminishing since we have been getting away from cast iron and steel piping. There is a reason we chlorinate and flush sections of water main....look at the build up you get in your shower head?...then multiply it by???? a zillion ?
Mostly it was accidental. The anti-freeze was on purpose. It tasted sweet.
So what's in our city water mains?
Cryptosporidium parasites,neurological drugs, high blood pressure meds,anti-inflammatories,antibiotics,reproductive hormones.
Rust,minerals of various kinds.
Some of dis, some of dat.
,
I have worked water treatment and distribution.
One example is a small community hooked up to a rural well a few miles away. The pipe laid stacked up, no plugs in the ends, for weeks. The pipe line was completed and at the water tower there was a screen that had to be cleaned daily. It contained the hair, guts & bones of the little critters that nested in the pipes.
Another example is a water tower’s topside ventilation screen became dislodged. It was never inspected by the city employee. When the state inspected it, it was discovered birds got in a were crapping in the water supply. There were several inches of dead birds and bird crap sediment at the bottom.
There’s a good reason for chlorination.
Don’t get me going on bottled water that is not chlorinated. (A hint: any bacteria or other contaminant can get in it during bottling)