How long does THC stay in your system?

I want to know specifically how long it stays in your body. Assuming that you shared maybe 3 or 4 bowls with a friend (what I normally do), and drink about 6 to 8 cups of liquid(mostly water/water based) a day. Just wondering, because I have to take a drug test for a job in two days and I don't know if I should take some pills or just drink a little extra water. Oh, and no I'm not fucked because last time I got high was a week ago.