I have a son who just turned 18. He lives at home, maintains about a 2.8 GPA at a private high school (Catholic), played water polo for three years and is generally a good kid: tutors, drives a car that he half-paid for, does chores around the house, drives his brother to school. He has (knock on wood) never been arrested and is on track to attend a decent college (given his GPA), with four apps already out. Our one, and only, issue (aside from better grades) is pot. Two years ago, we discovered him in the backyard smoking with a friend. He apologized profusely. I destroyed his pipe and made him give me his 'stash,' which I flushed down the toilet. We had a few more incidents since then, always with the same end - apologies, confiscation and often grounding/losing phone privileges for a week or two. The inherent problem, though, is he sees nothing wrong with pot use. He calls it the new beer, and always said he only smokes a little once or twice a month. He turned 18 in October. Now, he informs me he is an adult and won't stop smoking pot. He promised to never smoke before driving, but "it relaxes me and everyone does it." I smelled it a few times and he admitted smoking in his room. I said that is completely verboten. I also told him I don't want to search his room because as an adult I want to respect his privacy, but I don't want the illegal substance in his room. He argued there's nowhere else to keep it, and besides he smokes a little every day. Last night it was raining. Marijuana smell from his room. "It's raining," he said. I blew up. I said not only has he completely disregarded my admonition to never, ever, smoke in the house, but it was so strong I feared his little brothers might catch a whiff of it. I said I am imposing a $20 fine that will go up by $10 each time I smell it in the house (in return for various chores, he gets an allowance of $100 per month) and gave him until 8 tonight to get rid of his stash. Big resistance. Went through the whole "18 talk:" He says "I am 18 and can make my own decisions." I said, "You still live under my roof, so my rules." At loggerheads. Key issue is he sees pot as no more threatening than an occasional beer, while I see it as a destructive "stupid" drug that demotivates him and can cause lasting damage to his mind. Plus, it is illegal. But I don't see any resolution unless/until he realizes it's bad for him and wants to stop. Where do we go from here????