In my country, drinking water supply is always/often contaminated with sewage water & fecal matter too. is it possible to get c.diff from such water? how to protect myself from getting c.diff as boiling doesn't kill c.diff? any other option/s?

Ignore the issue: C. diff can be a chance contaminant in the normal gut occasionally. It does not always act as an aggressive germ & cause harm. Those with a compromised immune system or who have been treated for invasive germs with repeated antibiotic exposures that kill off friendly gut germs are at risk. Wash your hands often. Be aware. Take probiotics (good germs). Live life as well as you can.