What kind of test are you taking? Do you know the cutoff limit what they are testing for? Most civillian type tests are at 50 ng cutoff. There is no specified time limit but a rule of thumb would be if you smoked everyday for a year it could take 30+ days, if you just smoke once (a hit or two) every few months, 1-6 days. The best friend in your situation is time, water will only dilute your urine. Start taking a multivitamin, one that has creatine if possible and high levels of vitamin b and niacin, a good one is Mega Men from GNC, the metabolism type. If you know exactly when your test is going to be, you are in luck! You can beat the system by drinking plenty of water before hand, and pissing at least 5 times before the test, by that time your sample should be diluted down enough to not test positive. If it is just a dip stick test you will be good with this method, if its sent to a lab it will be more difficult, however as long as they are not testing for ph the dilution method will work. If you keep creatine in your diet, red meat the day before has alot of natural creatine, sugars. Stay away from coffee, you can even drink an energy drink before hand.
1. Drink lots of water, be careful not to over do it, you can "overdose" on water and dilute the important amino acids in your body and go into shock. If you are pissing every 12 oz bottle, thats good! STAY HYDRATED!
2. Take multivitamin
3. Exercise
4. Pee 4-5 times before you submit the sample, whatever you do, DO NOT use your first pee of the day as this will be the most potent!
5. When submitting the sample, pee in the bowl then when in midstream pee in the cup, then pee back in the bowl! Your "cleanest" specimen will be in midstream.
6. Hope that you're clean!
7. Be weary of the "masking solutions" as they do not always work.
Good luck!