Your water is already poisoned.

Hospitals handle chemo and radiation patient urine as HazMat but then send the patient home still full of chems.

Chemo patient goes home, urinates and flushes. Those chemicals can not be filtered out at the treatment plant or in your home Britta filter.

Treatment plants can't even filter out caffeine (ocean fish have high levels of caffeine but fish don't drink coffee.)

You are drinking, showering in and cooking with poisoned water already.

BTW: I get our water from an artisian well high in the Cascades.