Holding tank odors are a definite problem experienced by the vast majority of RVers. But there is good news; relief is available! By following correct waste management practices, checking for proper venting and by using a few aftermarket products I recommend you can all but eliminate and certainly minimize those dreadful odors that seemingly plague us all.
First, fully realize that odors can originate in either the black water or the gray water holding tank. Foul odor is not limited to the toilet tank only!
That said, let’s take a look at a few areas within the RV waste system.
Venting
One important aspect of proper RV waste management is understanding the dynamics of holding tank venting. Each holding tank must be vented from the holding tank up and through the roof to the outside atmosphere; the typical vent consist of 1-1/2″ ABS plastic piping. Here’s an issue — Oftentimes coach manufacturers cut a very large hole in the roof for this vent pipe to pass through; it makes the installation a little easier. Sometimes this vent opening may not be sealed properly all the way around the pipe. In other cases the vent pipe itself may not extend far enough above the roof line. According to the NFPA 1192 Standards on Recreational Vehicles, “each vent pipe shall pass through the roof and terminate vertically, undiminished in size, not less than 2-inches above the roof.”
But if you have a short vent pipe (less than 2-inches above the roof), and the area around the pipe is not sealed and an oversized hole exists, then it is entirely possible for tank odors to pass up the vent pipe, hit the roof of the sewer vent cap and bounce back down beside the pipe into the ceiling area where it makes its way to the living area and you inhale the results. Not all tank odors are lighter than air!
So, from the roof, pop of the top of each sewer vent on the rig and be sure the area around the vent pipe is sealed properly (no gaps anywhere around the full circumference of the pipe) and that the pipe itself stands at least two inches above the roof. Extend it by using an ABS coupling and a short piece of pipe if necessary.
In some cases, depending on the method used to connect the vent to the top of the holding tank, vent pipes have fallen down inside the tank, nullinfying any venting action whatsoever and allowing tank odors to exhaust well before the roof line, virtually within the ceiling void or even inside an interior wall pocket trapping odors inside the living sections of the RV. By inspecting the vent regularly, this can be avoided.
I actually recommend replacing stock sewer vents with one of my favorite aftermarket add-on products; the Xtreme Vent produced by Coil n’Wrap.
The vent rotates 360-degrees and is made of heavy duty metal as opposed to plastic. This vent is indeed durable. The pivoting action is very smooth and it captures even the slightest wind. A 1-MPH breeze entering the vent opening creates 4-MPH air movement inside the vent pipe. Just imagine the effectiveness of ram air while driving down the road! The air moving through the vent actually sucks odors and vapors out of each holding tank. The faster the incoming air, the quicker vapors are drawn out of the holding tank. Installation is very simple; any handyman can replace an existing sewer vent with an Xtreme Vent.
Another added benefit, although I have not yet personally substantiated it, is that the lowered static pressure creates an oxygen rich environment inside the holding tank, thereby maximizing hte efforts of the natural (or added) enzymes breaking down the solids and tissues faster and purportedly more completely.
That’s it on venting; in my next few posts I’ll talk about additives, waste system components, holding tank blockages, and corrective evacuation procedures and how they can assist with controlling odors in your RV.
Gary Bunzer, The RV Doctor