I think you have bigger problems than that. Your son is smoking pot (which I don't think is a big deal by itself). Talk to him make sure that whatever his experience is he doesn't go beyond the healthy threshold.

it will stay in his system for 30 days and yes it can show a positive result if someone was smoking near him if he had contact with the smoke

DUPLICATE. Please try a search before you post questions.

It usually takes 30 days for it to be out of your system...some people may take longer..it really depends on a lot of different factors...but like I said usually 30 days.

Well since my last long answer just got deleted because I wasnt signed in, I'll make this short. I was in the military for several years and smoked just about every weekend and never failed a single drug screen. This is how I done it- For drug screens I suggest 2 products. One is called surejel and can be found in any grocery store by the geletin. What this does is masks the THC cells(which are similar to fat cells) by coating them with geletin the down side to this is after mixing it up with water it tastes absolutely horrible and only works for around 5 hours. Another method (and I suggest using both) is actually cleansing this can be done by drinking lots of water and using water purification pills.The water purification tablets can be found at any wal-mart in the camping section a good product is called potable aqua The water purification pills are simply Iodine tablets used to purify questionable water in a survival situation. The downside to this is that the iodine tablets have been known to cause damage to kidneys if used for a prolonged time. So only use them at most every 2-3 weeks. From one smoker to another I hope this helps. Its not quite as informal as my initial answer but im sure it will more than help. Happy smoking and may big buds and clean piss be in your future

The normal consuption amount of water for a human weighing 150lbs is 65.963 US Ounces Of Water. With that you would need around 27 days of drinking that solid to pass a drug test. Increase the amount of water the days do go down but thc is similar to fat cells and actually cling to them. So the higher percentage of body fat the more time it will take to become clean of thc. Also you can actually overdose of water. Go to the link if you dont belive me http://en.wikipedia.org/wiki/Water_intoxication . Well since my last long answer just got deleted because I wasnt signed in, I'll make this short. I was in the military for several years and smoked just about every weekend and never failed a single drug screen. This is how I done it- For drug screens I suggest 2 products. One is called surejel and can be found in any grocery store by the geletin. What this does is masks the THC cells(which are similar to fat cells) by coating them with geletin the down side to this is after mixing it up with water it tastes absolutely horrible and only works for around 5 hours. Another method (and I suggest using both) is actually cleansing this can be done by drinking lots of water and using water purification pills.The water purification tablets can be found at any wal-mart in the camping section a good product is called potable aqua The water purification pills are simply Iodine tablets used to purify questionable water in a survival situation. The downside to this is that the iodine tablets have been known to cause damage to kidneys if used for a prolonged time. So only use them at most every 2-3 weeks. From one smoker to another I hope this helps. Its not quite as informal as my initial answer but im sure it will more than help. Happy smoking and may big buds and clean piss be in your future. Rate Answer

They're is abosoutley nothing wrong with marajuana. Don't worry. You'll son will be fine, the drug is harmless in all ways. It's better to let himexperiment they lie to you.

Despite what you've read here, any judge will tell you that weed does NOT show up in your system from second hand inhalation unless they forced your son into a small closet while they were smoking it. A car with windows rolled up will do the same thing, but it will also sting the eyes of a driver, so this is an unlikely scenario. Detectable THC levels remain in the system for about 30 days. However, diet, sweating and other factors can and do influence this number. 30 days is only an average. It can remain in someone's system longer. +5

How old is the kid and why would you do that? My daughter went to a beer party when she was 13. I asked if she was drinking and she swore she was not. I said o.k. then you must be on drugs and took her to the hospital emergency room. I gave here one more chance to confess and she didn't. I went to the check-in desk and loudly announced that I wanted a drug test for my daughter. You could see my daughter cringe in embarrassment. So they did the test and she had a bit of alcohol but no drugs in here blood. That was the last time any problems came up. The public embarrassment and the certainity about my reaction was enough to change her attitude.