Dumping RV tanks into home syptic system

[SteveAE]

For the five or 6 years that I have been RV'ing, for convenience, I would sometimes dump my tanks into my home septic system upon returning home. While I have felt pretty comfortable doing this, I have also wondered if there was any potential for damage (to my home septic system) from this practice. So, when the tanks were especially full, I would sometimes throttle the flow so as to only allow part of the tank(s) to dump at a time. Give it a moment or two to settle, then dump some more.

Today, when I had my septic tank pumped (I do it every 5 years), I took the opportunity to raise this question with the pumper.

I learned that IF chemicals are used in the RV holding tank AND this dumping is done frequently (i.e.; > 12 times per year), then over time, these chemicals will build up in the septic tank enough that they start to liquefy its contents. If the contents of the tank liquefy (they are supposed to separate; with solids at the bottom, water in the middle, and a scum layer on top), then this "slurry" makes its way past the outlet sanitary tee (located in the center of the tank and designed for only water to pass) and into the drain field. On the other hand, if this dumping only happens a few times per year (6 to 8), then it was his opinion that it "isn't likely" to cause a problem.

When I told the pumper that I don't use chemicals at all, he responded that I "can dump as much, as fast, and as often as I want". The inlet tee will slow down the flow so as not to cause turbulence in the septic tank and the contents will be digested by the natural process in the tank (not liquefied as the RV chemicals "eventually" do).

This made sense to me so I wanted to share it with the RV community.

Happy dumping.

[korbe]

My general instinct on the subject would agree that the "chemicals" used for keeping the holding tanks smelling rosy can't be beneficial for the processes that are taking place in a normal septic tank. And I never did understand the talk of overloading your tank with a dump from the RV. The tank & leachfield sizing is based on average flows, not peak flows.

[Homer1]

For many many years I have dumped my black and Gray into the clean out of my septic and later the city sewer system. I also do not use chemicals of any kind. Nature takes care of that, if you do not dump tanks too often. I never had to have my septic cleaned, and the city sewer I did not worry about. I did ask the city sewer mgr about dumping into the city system, and his words to me; it does not care where the sewage came from, it is built to handle it.

[lanerd]

Every five years? Wow. I just had mine pumped after 24 years. Of course, there's only the two of us.

I dump my tanks into my septic tank once a year upon getting home from our last trip. However, I usually only have just a small amount in it as I also dump at our last stop. I do use a macerator so that the flow into the tank is no where like the flow from a stinky slinky. I also do not use any chemicals except for laundry soap.

We've been doing this for the past 15 years and have not experience any problem. We only had the septic tank pumped because we had a blockage on the main line from the house which didn't affect dumping the mh tanks into the clean out right next to the tank. Figured while we had the line dug up and replaced, might as well and have the tank pumped.

Ron