Many EHM programs include an alcohol monitoring component. However, they usually do not test for drug use. So long as your probation does not include a no use or testing provision, you should not worry about someone showing up to test you.
The best advice for you is to stop committing crimes while you are on probation....smoking marijuana is illegal. Although there is a good chance that you might not be drug tested by someone randomly showing up at your home, it is still not worth the risk of the consequences you could potentially face. I wish you the best of luck.