The reason is because only 80% of the THC in each bong hit will reach your lungs. The rest is either lost in the pipe or stuck in the water. Unburned herb may still be in the chamber as well.
Drinking bong water can cause extreme stomach pain and discomfort. Using an ISO alcohol extraction to collect the resin is much more efficient and healthy.
Bongwater is at it again.
What the GAC did Bongwater say?