Sunday, August 1, 2021
Sunday, August 1, 2021

Holding tank tips for the stationary RV

By Russ and Tiña De Maris

While the term “recreational vehicle” fosters visions of hitting the open road and exploring new sights, new civilizations, we don’t always boldly go where we haven’t gone before. Sometimes we may be “stuck” in the same place for a couple of weeks–even months. Having a “stationary RV” means special care of the black water holding tank.

smell-747First, NEVER leave your black water holding tank dump valves OPEN. Yes you are hooked up to a sewer line, but getting all those nasty solids out of your holding tank requires the movement of a large amount of fluid. More than one RVer has learned the hard way that leaving the black water dump valve open translates quickly into a holding tank that won’t dump.

When an RV rolls down the highway, it’s not just beneficial for us behind the windshield, seeing those new sights. Down under in the holding tank, that rock and roll motion the rig keeps the black water tank stirred up. This contributes to the breakdown of solids and the removal of foul odors. Park your rig and don’t move it for a few days, a different setup occurs in the holding tank. Solids tend to gravitate to the bottom of the tank and an ugly sort of transformation begins to occur. We’ll spare you the grosser details, but it needs to be said that a goop-like substance can begin to coat the bottom of your holding tank.

That goopy coating is hard to get out of the tank and if not evicted can begin to build up and up and can eventually cause a blockage. To keep this from happening, when you dump your blackwater tank (which should be done ONLY when the tank is at least three-quarters full), allow plenty of time for the contents to evacuate.

Here’s where having a clear plastic sewer hose-to-dump port adapter is a good thing to have. When you dump the black tank you can closely observe just what’s coming out of the tank. After sitting for a number of days you may be surprised just how s-l-o-w-l-y those contents can be about coming out of the tank. Slamming the holding tank valve shut before the contents are clear can not only leave you holding more gunk in the tank, the stuff can also prevent a water-tight seal on your black water valve–not a good thing.

If you find the tank just doesn’t seem to want to “get empty” then leave the valve open and have a helper run the toilet until the tank runs clear. We’ve found it may require a greater volume of water than the toilet itself will readily provide. We have a secret weapon: Our shower hose will stretch far enough to blast water down the toilet making the job much faster.

IN HOT WEATHER, stationary RVers face another problem: Sour tanks. The combination of heat and lack of motion can cause the breakdown of wastes in the tank to stop, causing a really, really stinky situation. Assuming that you are either not using any sort of holding tank treatment at all, or are using one that’s based on enzymes and/or bacteria, you may be able to clear up the problem by dumping a half-cup of baking soda down the toilet with a couple of gallons of water. This may “sweeten” an otherwise acidic condition, getting natural bacteria to begin waste breakdown, reducing the stink factor.

In really tough situations you may need to fill up the holding tank with water, dump it completely, and then add a couple of cups of baking soda and fill it up with water again. This time don’t dump the tank immediately; let the tank sit overnight, then dump it and “restart” the system with the addition of a bacterial and/or enzyme based holding tank treatment. We had this happen once during a hot spring stay on the Arizona desert. The stench was overpowering, but the “fill, dump, refill with soda water, dump again” procedure proved a life (and nose) saver.



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Sheryl Millar
5 years ago

We have one of those clear sewer hose-to-dump connectors, and it has been a LIFE SAVER! We use it every time we dump. My husband drains and flushes, drains and flushes, then we drag a water hose (specifically and only used for this purpose) into the bathroom and I put it down the toilet to add water from that direction. (This is when we’re at a dump station.) He continued to close, then open the valve, until the water runs clear. Then I add the chemical through the toilet and add a couple of gallons of water. We have a bit of odor sometimes as we flush–when it’s really hot outside–but overall, this gets the tank clean.

First travel trailer we bought back in 1988, which was used and in excellent shape, the people must not have heard of toilet chemicals. First time we camped in it and went to the dump station, lo and behold the sewer hose was too short! Well, we thought. We’ll put the end here and it will run into the dump station opening, and we’ll rinse it clean afterward. The stuff that came out of that hose!!!!!!!! Still nightmarish even after almost 30 years. We learned quickly–and rather rudely–about how to take care of the holding tank and how to empty it. Then we saw another camper with the clear connector and immediately got one for ourselves.

People may have to wait in line behind us at the dump station, but hey. They wouldn’t be the ones having to deal with the gunk and the smell. So we just smile and clean our tank our way.

5 years ago

Rid-X septic tank system is what I use when camped in the desert for the winter.. Never noticed a smell or had a problem in 8 years

Mark R.
5 years ago

We have found that when parked for a long time in one spot with your rv, before dumping the black tank, fill a bucket with at least 3-4 gallons of water and quickly dump it down the toilet. This will knock down any buildup. Then dump your tank. Repeat the bucket dump when your tank is empty. This will rinse any other residue. Finally, always have at least 5 gallons of water in the black tank after dumping. Sounds like a lot of work….but we’ve never had a stink or dump problem since.

5 years ago
Reply to  Mark R.

Good Job, Mark, I have found that to work very good also. Sometimes when you are at a dump site like a Pilots or in line at a campground you can’t do that so load it up with water so when you can it will dump quick.

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