How to kick a roomate out?

Ok... I have lived in my apartment for over 4 years now and I had a acquaintances move in two years ago. Here is the story, Before he moved in I stressed the importance of being punctual with rent. I am never I mean NEVER late when I pay my rent. Just not my thing... So I told him that rents due on the 1st of the month. He moved in on the first and he will pay on the first... I pay my rent on the 12th to my landlord. I am the only one on the lease but he knows that this kid is living with me. So anyways, The first 2 months he paid on the 1st of the month. Then he started slipping little by little. So I would send him text about rent money. He would never reply back and some money would be left on the kitchen table. The kid doesn't hang out in common areas of the apartment. For granted there is only the kitchen, living room which is tiny by the way 9x12 . So he basically lives in his room.. So he would leave like half of his 400 dollars he needs to pay for rent. 400 dollars. That's it. The kid makes at least 450 a week. I think he has a drug problem and I know he has a booze problem. I could go on for ever with this kid, but I will keep it to the main things that bother me. So dumb me I get cable in my name, because I want to watch tv and don't want to risk it getting shut off. However I have asked the kid not to smoke in the house. He does it in his bedroom. how nasty is that. Smoking in a bedroom, talk about 2nd and 3rd hand smoke. So here's my question, how do I ask this kid to leave. I can be the biggest and if it came to fisticuffs I def would handle that battle. But Im not a little kid anymore so I don't resort to that stuff to get my point across. What do I say to the kid. He never pays rent or cable on time. Usually 2 to 3 weeks late. He never showers. Hes lived here for 2 years and i might have herd him showering like 15 times. No exaggeration. He def isn't a healthy person. doesn't replace toilet paper...He has never cleaned the apartment once. Granted he lives in his room the whole time. I could go for days.. My only concern is in these tough times it isn't a bad idea to save when you can. Saving 400 a month on rent isn't bad..But I wouldn't go broke either if I booted him out. What do u think ????