Light smokers with an active life style and fast metabolism can be clean in as little as 2 weeks. Heavy smokers with a slow metabolism can take up to 45 days. Go easy on the fats in your diet- this forces your body to use the fat where the THC metabolites are stored. Take "B' vitamins (it will turn your urine yellow). They give you energy (burn that fat) and because of their color, they will mask the fact that you are trying to dilute your urine. Watch it on the drinking of water. Kids have DIED because they drank too much of just water- the minerals in their blood get too diluted and it causes a heart attack. No, I'm not kidding! Gatorade, chicken soup and/or milk should be drunk instead of just water. You don't need to "flush" your system with liquids for days and days before your test. One or two days are enough. Take a "B" vitamin the night before and maybe one that morning. Do not give your first or second urine of the day for your sample. Urinate at least twice before taking the sample. Do the collection from the middle part of your urination. Good luck!