I thought emptying our travel trailer’s black and grey water tanks was going to be absolutely disgusting, but it’s turned out to be not such a terrible job. If you’ve had an RV for a while, you’re probably an old hand at emptying your tanks, but if you’re new to RV life, I may be able to offer you a few tips on how to do this task quickly and efficiently.

If you’re squeamish about bodily waste and gag at the thought of getting your hands dirty, wear gloves. You can pick up boxes of nitrile or vinyl gloves pretty cheap at Harbor Freight. The Wal-Mart pharmacy department and most drugstores carry latex gloves; Wal-Mart usually also has disposable gloves in the paint department. Of course, single use items have a negative environmental impact, so you can do your part for Mother Nature by wearing heavy duty, reusable kitchen gloves when you’re emptying your waste tanks. After you’ve done your dumping, store your gloves with your sewer hose so you can always find them when you need them.

Speaking of sewer hoses, longer is better. When we bought our sewer hose, The Man and I agreed 10 feet of hose would be plenty. If I had known then what I know now, I would have purchased a hose that was 15 or even 20 feet long. Our hose has never been too short, but we have had to stretch it to its limit to get it to the drain a couple of times. Sometimes it’s challenging to pull the trailer to within ten feet of a dump station drain. If we had a longer hose, The Man wouldn’t have to work quite so hard to get the trailer quite so close to where we need it to be.

While shopping for RV accessories, we saw the special, expensive RV/marine toilet paper that’s supposed to break down quickly. We contemplated buying the special toilet paper, but decided against it. We already bought the cheapest toilet paper any store offers, and The Man had read testimonies online from people who didn’t feel the need to use special toilet paper in their RV toilets. BIG MISTAKE! We ended up with toilet paper not breaking down and clogging our system. Now we do not put ANY toilet paper into our toilet. Used toilet paper gets put in a covered wastebasket next to the toilet. We line the wastebasket with a plastic bag, and when the bag is full it’s removed, tied shut, and disposed of with our other trash.

We still have not tried the special RV/marine toilet paper. After dealing with the clog, we decided not to take any more chances. From our lives as vandwellers, we were already accustomed to dealing with our own waste, so a little toilet paper in the garbage can doesn’t disgust us. Dealing with toilet paper in a garbage can is a LOT easier than dealing with a clogged black water system.

Our travel trailer has an indicator to tell us how full our black and grey water tanks are. At the touch of a button, lights indicate if our tanks are empty, ⅓ full, ⅔ full, or full. When we picked up our travel trailer, the indicator said the black water tank was ⅔ full. The fellow who serviced the trailer said he’d emptied the black water tank, but later we wondered if he’d forgotten to do so. He also told us that sometimes a piece of toilet paper stuck in the tank can trigger a sensor and tell you the tank has waste in it when it doesn’t. Because we didn’t want the extra weight of a full black water tank while traveling or the problems caused by petrified poop in the tank, we were determined to make sure the tank was empty. After using enzymes in the tank, adding 5+ gallons of water, and dumping three times within five days, our indicator finally showed the tank was empty. Yay!

However, after using the toilet only a few times, the indicator showed the tank was ⅔ full again. Weird and impossible! Coyote Sue (a veteran of a number of motorhomes and pull-behind trailers) told us that most people with older RVs don’t rely on the holding tank indicators, but instead develop an understanding of how long they can go between dumps. Coyote Sue also keeps a logbook where she writes down where she stays each night, what she likes or dislikes about the place, and when she dumps her tanks. I’ve started keeping a logbook of our own, so I can look back and see when we dumped our tanks. We know if we dumped Sunday (for example), there’s no way we’ve filled the black water tank by Wednesday, no matter what the indicator tells us.

During our endeavor to completely empty our black water tank, I discovered that enzymes are not just to solve problems, but to prevent problems too. I didn’t really know what I was looking for when I stood in front of the RV toilet system enzymes display in Wal-Mart. There were at least a dozen options to choose from, including liquids and powders that had to be measured and poured, premeasured liquids in little bottles, and toss-ins which consists of powder in a membrane that breaks down to release the powder (a lot like laundry pods, I suppose).  A sign at the dump station at Rockhound State Park prohibited the dumping of formaldehyde (and a handful of other chemicals I’d never heard of), so I chose a liquid labeled “natural” and “no formaldehyde.” I also bought a measuring cup set at the Dollar Tree so we could divvy out the right amount every time and have a cup that was dedicated to only this job. (To my chagrin, The Man simply pours into the toilet the amount of enzymes he thinks we need at any given time without bothering to measure.)

After we emptied the first bottle of enzymes (I think the brand name was Thetford Campa-Chem Natural RV Holding Tank Treatment) we bought Unique Camping & Marine RV Digest-It brand at Ace Hardware. It costs us upwards of $13 per 32 fluid ounce bottle, but the instructions call for 2 ounces as the regular dose, instead of the 4 ounces per dose called for with the product I purchased at Wal-Mart. Since we use less of it, I think it’s worth spending a little more. Also, it seems to do its job, which definitely makes it worth the money.

None of the enzyme products I’ve seen say how often they should be used, so we turned to Coyote Sue for advice again. She said she adds an enzyme product (I believe she uses toss-ins) after dumping her tank, then again about a week later. She typically travels alone, so she may need to add enzymes (and dump) less often than The Man and I do.

We’re not really campground people, although we did stay in one for a week while working on the road to our property. Our campsite included hookups to electricity, water, and sewer. I’d already read about proper sewer hookup procedure, but the host at the campground reminded me of what to do. While hooked up to the sewer at a campground, keep the black water tank closed until it is ⅔ full or until you are ready to dump before leaving. If you leave the tank valve open while connected to the drain, the liquid will drain away each time it’s added to the tank and not be there to help flush out the solid waste. Your sewer hose will get clogged if you leave the black water tank open, the camp host put it delicately while wrinkling her nose. I wonder if she knew this from personal experience or from watching other campers.

Whether dumping into the sewer drain at a campsite or at a dump station, dump the black water tank first, then the grey water tanks. The grey water should be less gross than the black water and will help wash the black water grossness away. After dumping and disconnecting your sewer hose, you can use fresh water to give the hose a good rinse, making sure all waste water goes down the drain.

So there you have it: everything I’ve learned so far about maintaining an RV’s grey and black water tanks.

If you have RV experience, what tips can you offer a newbie like me? Please leave a response in the comments below.

I took the photo in this post.