I know this thread is old but for people who read it and wonder, drinking a lot of water or fluids days before the test is useless. As long as you are properly hydrated you will not be able to raise your kidney's filtration rate by loading up on water. You kidneys will regulate your blood volume to adjust for the increased water intake and you will not be able to increase your kidney's output of THC metabolites.

FBR on the Dilution sticky! I think I mentioned it not affecting the liver, but this is the correct version of what I said.