RV Doctor
RV Doctor explains how to unclog a kitchen sink
By Gary Bunzer

Dear RV Doctor,
The kitchen sink in my motorhome is stopped up and water is standing in it. What do I do to clear the drain? -- Linda Brown

Dear Linda,
It sounds to me like a simple blockage in the "P" trap or in another section of the drain piping at or near the sink. If you are not experiencing a stoppage at the lavatory sink or the tub/shower than perhaps this is an isolated incident.

I would avoid using any of the aftermarket drain cleaners like Drano or Instant Plumber: some may be harmful to the "O" rings in the termination valves or to enzyme-based holding tank additives. I would suggest a somewhat messy though much safer method. Find a pan that will fit under the "P" trap under the sink. It's best to remove everything from under there anyway, just in case some water spills out. All RV "P" traps are removable by simply loosening the ring/nut at the middle of the trap as well as the uppermost ring/nut on the sink drain. They are probably not very tight and in some cases can be loosened by hand.

Next, remove fully the uppermost nut and slide it up towards the sink. It may be necessary to completely disassemble the entire "P" trap, but in any event you'll want to remove it from the plumbing. This will allow all the sink water to drain, so be sure the pan you choose has a capacity larger than the sink contents. Chances are the blockage will be in the trap itself or just into the drain pipe as it exits the trap.

Usually the blockage can be removed by flushing the trap segments out with a garden hose. If the blockage is further downstream it may be necessary to "snake" the drain with a small probe. Drain snakes are readily available at most home centers or hardware stores. You should be able to insert the snake right there under the sink and reach all the way to the holding tank, thereby clearing any blockage. By the way, it's not a bad idea to periodically remove and clean each "P" trap in the RV.

Gary Bunzer, The RV Doctor, is a well known RV author and the host of RV Roadtrips, the DIY Network cable television show. He is one of the RV industry's most sought after speakers and the host of the popular DVD titled Do It Yourself RV Care.

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