you can just make it so they can't test your urine. If your urine is too clear, as in you are too hydrated, then there is too much water in your urine, therefore dilluting it. For THC levels, they test what percentage of your urine sample is THC. So if you are pissing clear, there is a lot of water in it. I had to get drug tested once, and I didn't knwo this, and since I played premier soccer, I was always hydrated. They told me they couldn't use my piss because it was too clear. So I had to come in the next week. I passed.