They can call bong water paraphernalia, but that's it. It's just a component of the bong, a filter that the substance goes through, it's not a drug itself. No one drinks or injects that shit, not unless they lost a bet. Even if they did, they would feel very little if any effects, unless you're the lady who smoked meth out of it.
But charging someone as if it were a controlled substance? It's an underhanded scare tactic to freak people out about using drugs because of the absurdly steep consequences, the 'war on drugs' is an utter failure and this era of 'prohibition' will be remembered as backwards, arrogant, and short-sighted period in our law system. You can't wage war on human nature.