Jeffrey Nicklas Sr wrote:Right side of dual kitchen sink backs up even when not being used. My question is, can I use over the counter drain cleaners like Draino or Liquid Plumbr to clear?

Thanks, Jeff

I have an 07 Fleetwood. The material used for sink plumbing appears to be the same as you can buy at Lowe's and I have done so to make repairs .  I believe that you can use drain cleaners.  I would flush with lots of water to avoid any holding tank concerns.