11 years old, peeing in his pants..

We have an 11 year old foster son. He is diagnosed with ADHD, PTSD and some self harming behaviors. He is a great kid, but is VERY lazy when it comes to personal hygeine, which I'm guessing is typical of an 11 year old boy. He was in a couple different residential facilities with very strict personal hygeine rules (showers and laundry were done on a schedule). Well he is doing great at our house and has told his therapist and case manager that he loves it here. I am with him all the time and I can usually tell when something is bothering him. Lately, though, I have noticed that his clothes REEK of urine. I only smell it after the clothes are in his hamper though (or even worse- when they are in the dryer-yuck). It's disgusting. I had a talk with him, and tried to make it very matter of fact and non-threatening. He knows how to use our washer and dryer and I told him that if he has an accident, he needs to immediately wash his clothes. I also told him that I expect him to realize when he feels the urge to go to the bathroom, and to make sure he is only using the toilet when he has to go. He said "ok" but it has continued. This started only about a week ago. Then I noticed yesterday that there were "streak marks" in his underwear (#2). He gets very frustrated with me when I try to talk to him about personal hygeine related issues. I am soooo tired of repeating myself though, and I am just wondering if it will ever pay off. We have problems getting him to take showers, brush his teeth and ESPECIALLY getting him to wear deodorant. I've bought him the name brand, "smell-good" body wash, shampoo and deodorant that he wanted, hoping it would encourage him to want to shower, but it hasn't worked. He sometimes turns the shower on and never even gets in it. My fiance has talked with him, and so have I. He'll use the "oh, I forgot" line about deodorant, and I frequently pick him up from school and realize he obviously isn't wearing any. I don't want him to be made fun of by other kids, but his body odor really can be quite offensive and I can't get him to realize it. I already nag him in the morning- "Did you turn your bedroom lights off? Do you have your homework? Did you brush your teeth?" and that usually adds 15 minutes to our morning routine because he says he did things when he actually didn't, and he doesn't do any of those things without me telling him to. Do you have any advice? I guess I am having a hard time finding a balance between nagging 24 hours a day (and trust me, it wouldn't be hard) and being someone he can talk to. I'm not trying to be his "friend", but I also don't want him to be afraid of me. He has such a tragic past and so much to deal with emotionally, that I worry I will overwhelm him with all these "rules"... but I also worry he will go into adulthood not knowing how to keep himself clean. This peeing in his pants thing is absolutely disgusting to me. I had a dryer full of clothes and for some reason, he put his clothes in the dryer with mine and they REEK of urine now. I'm ready to just toss all the clothes, that's how awful it smells.. PLEASE HELP!