Thursday, October 6, 2022


RV Education 101: RV gray water tank maintenance tip 

By Mark Polk

We always talk about black water holding tank maintenance, but seldom mention the gray water holding tank. The gray water tank requires some simple maintenance to keep it clean and odor free.

After I empty both holding tanks, I add water to the gray water holding tank. Add enough water to cover the bottom of the tank. Next, add a gray water tank treatment or some Dawn dishwashing liquid in the sink drain and run water long enough to get it past the p-traps and into the holding tank.

Now, when you drive or tow the RV, the water and detergent will suds up and move around, cleaning the inside of the gray water holding tank.

Motorhome RV Orientation®
Travel Trailer & 5th Wheel RV Orientation®

Mark Polk’s tech tips are posted every Saturday in the RV Travel Newsletter and every Wednesday on the RV Daily Tips Newsletter.



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10 months ago

Water doesn’t slosh and splash around it the holding tanks as much as folks think.
Watch the video with the clear tank and ice cubes. Not much movement at all.
Unless, of course, you autocross your RV. Lol.

Ron Lane
10 months ago

Article says the Dawn will “suds up”. Then what? Do the suds drain the next time you drain the tank or does it dry out and put a film on the inside of the tank? Not sure if that is a good thing or not. In any case, instead of using Dawn, why not use a liquid laundry detergent that is designed to not only cut oil/grease (just like Dawn) but without all the suds?

Montgomery D. Bonner
10 months ago

Or, you can use these tabs. I break in half, one half in the bathroom, one half in the shower. We keep screens in the kitchen sink to catch any debris from washing dishes. Convenient, and does excellent job. Dawn is possibly cheaper. I used to use a powder cleaner in the Black tank, but it never dissolves totally, and ruined one of my gate valves, so, now use nothing but liquids in them. You can use a powder, but make sure it’s mixed up completely and then put down drain or toilet.

AmazonSmile: Walex TOI-61776 Elomonate Grey Water Deodorizer Tablets – 5 Pack : Automotive

10 months ago

I try not to let any large food particles down the kitchen drain so I use a fine mesh drain screen that I purchased at Home Depot. Second, I put about a tablespoon of Rid-X down the drain after every flush. Third, I always use Dawn dish soap. Fourth, I always travel with several gallons of water/Dawn in both tanks to slosh around and dump ASAP while setting up. Results, tanks are clean and sensors work 90% of the time. It would be interesting to see if a gray tank rinse system aimed at the sensors would be of any help!

10 months ago
Reply to  Joe

Finally ! Someone else is out there who uses RidX in tanks.

Donald N Wright
10 months ago

Dawn dishwashing soap? How cheap & easy this is. Thank you.