carpet cleaning an rv

I also rent one of the commercial carpet cleaners and use it once with the shampoo/cleaner - suck it all up and then refill with clean water and go back over again. You won't believe the dirty water you get up again the 2nd time. After I started doing this I didn't have the problem of the carpet looking dirty again in a short time after cleaning it. That soapy residue just attracts dirt. I rinse every time now. We are full-time and I try to do it 2X per year. After 4 years living in it, the carpet still looks good. ( We do have a dog too)