By Nanci Dixon
This all started when our suction cup soap holder in the shower fell off the wall. No big deal —it falls off every couple of months when jostled too much, or the suction cup dries up. I decided to clean the soap residue from the soap holder and, while at it, I cleaned another soap container. The soap didn’t just rinse off, and both items needed a good soak.
The bucket I was soaking them in ended up full of soap scum, and I realized that the residue in the bucket was a microcosm of what must be in our gray water holding tank. It was time to clean.
Prevent “stuff” from getting into the tank
First, prevent the stuff that sticks, clogs, and stinks from getting into the gray water tank. Start at the source.
- Use a kitchen sink strainer and a hair strainer in the shower. We use this one in the shower after getting a long hair clog (mine)—it works great! Sizes vary, so double-check the drain size if ordering.
- Scrape and wipe off dishes well before washing.
- If using an RV dishwasher, be aware it is not connected to a garbage disposal like home dishwashers. The dishes need to be scraped and food particles wiped off, too.
- Clean your sink strainer by lifting and wiping down periodically. Pick out any scraps that have made their way into the drain.
Add cleaner to the gray tank
Add cleaning agent to the tank. Do NOT use bleach. Bleach is hard on rubber and can damage valves and seals. There are a number of recommended cleaners. While any of these will work, Dawn dish detergent is the most popular, both because of its grease-cutting ability and being readily available.
Recommended cleaning agents
Choose one (only one!) of the suggestions below.
- 1/2 – 1 cup Dawn dish detergent—this is one of the most popular
- 1/2 cup Calgon water softener and 1/2 cup dishwashing detergent
- 1 cup dishwasher gel
- 1 cup baking soda
- 1 cup laundry detergent
Fill the gray tank with water and drive around
Fill the gray tank with water. Drive your RV around and let the cleaner slosh around and break down the gunk. Let the cleaner stay in the tank for a day or two, if possible. This is a good thing to do when traveling and stopping at another full-hookup site.
Dump tank and rinse
It is good to rinse the tank at this point if you have a tank rinser or sewer hose rinse adapter. You can get the adapter here. This is a 45-degree one, but there is also a straight flush attachment available.
Add treatment
You can add 1/2 cup to 1 cup of dish detergent or any enzyme-based gray water treatment to help keep the tank clean after dumping.
Some people add a treatment every time after dumping, and others only the second or third dump cycle.
RELATED
- How to deal with gray water tank odor in your RV
- That stink in your RV is probably the unsuspected gray water tank
- Quick RV Tech Tip: Why doesn’t my gray water tank drain completely?
- RV Education 101: RV gray water tank maintenance tip
RVDT2845
I would not use Dawn in my tanks and drive around. I have found that it suds up and prevents the cleaning of the tank walls. Instead I use Cascade Platinum dishwasher pods. I break several of them open, drop them in the tank and then drive around. Very low suds, and much better cleaning of the tank walls.
Or even laundry detergent. That and a water softener like Calgon. Low sudsing and also breaks down grease.