"Chronic smoking of marijuana can lead to respiratory ailments associated with smoke inhalation. A
1995 study suggests that use of a bong or water pipe does not necessarily lower the overall ratio of particulate matter to THC and may be counterproductive. In other words, it lowers the particulate matter, but it also lowers the amount of THC. For the same effects, a person may have to smoke more...thus raising particulate matter back to a level equal to that inhaled from unfiltered sources (joint or pipe)."
http://www.erowid.org/plants/cannabi...s_health.shtml
This tells me that bongs are a waste of money and are only good for taking less harsh of hits if you have to money to spend on more weed.........