Why does my dog continue to pee & poop on my area rug?

Okay, so I am having this little problem. My dog is peeing and pooping on my living room area rug. This big fluffy beautiful rug. It's brown so sometimes it is hard to see the poop and it gets stepped on and therefore, smeared into the rug. So now I have to wash it. I sometimes would hang it up outside and spray it down with the water hose, but now it is cold. I can no longer just throw the rub outside. It is in the basement as we write. I do not know what to do about this. The dog does fine when I am home. I let him out and he does his business outside. He used to poop & pee on the rug while I was gone, but I got smart and started putting him in the basement while I am gone. So now he does it during the night. I let him out right before we go to bed. And last night I let him out around 3am also. He still pooped on the rug and I found it in the morning. What should I do? Any suggestions? Lock the dog in the basement at night too? I really don't want to do that. I don't have a carrier to crate him at night either. I have tried rubbing his nose in it and spanking him. I am in desperate need of suggestions before my rug is ruined. If not from him, then the washer.