RV dump on old septic system

[charlz]

I recently purchased a used 'Fun Mover' which is a Class C RV with a garage in the back for our dirtbikes :thumbsup: Guess I didn't have enough things to work on or spend money on

I have an old septic system at the far end of the property that used to service the original owners trailer. I am thinking of using this system as a home RV dump. Nothing is attached to the system (tank and drain field), just two old pipes that come out of a Y right off the septic tank. I am working on extending the one line to a spot where it would be convenient to park and dump the RV. Am I correct in thinking I should turn the other pipe into some type of vent? extend it above the ground with a 180 and some screen or something on it? My thoughts are this would be good because 1) the displaced air needs someplace to go when the sewage pours in during the RV tank dump... I probably don't want the RV hose 'burping' and maybe popping off/out 2) there should be a vent in the system anyway to prevent any pressure build up etc. in the septic tank (the pipe going to the RV dump port will be capped when not in use).

Thoughts?

 

[Gale Hawkins]

This is done all of the time and any adjustments in dump rate, etc you will figure out with time.

You may want to check out threads on www.rv.net on the subject too.

You sure will have a fulltime project now that you own a MH.

 

[mbohuntr]

Correct. I'm also pretty sure the RV tanks are vented, and if your dump pipe is larger than the hose, it will self vent to prevent "gurgling"

 

[Kays Supply]

You want the pipe going to the septic tank vented but not the tank itself. A septic tank functions antirobic ( without oxygen) the leach field fuctions aerobic ( with oxygen). Since you aren't going to be using it daily, a dose of some brand of bacteria every now and then, would also be helpful, Bio Clean , Robic, etc.

 

[charlz]

You may want to check out threads on www.rv.net on the subject too.

Yep, been reading over there like crazy I have seen where people put in extra piping at home for an RV dump but usually it is to an existing system, that is likely vented through existing vents on their house.

 

[charlz]

You want the pipe going to the septic tank vented but not the tank itself. A septic tank functions antirobic ( without oxygen) the leach field fuctions aerobic ( with oxygen).

So is there some rule of thumb on how far away from the tank to keep a vent? Right now the second pipe ends about 7 pipe-feet away from the tank. Would it be better to extend this at/above ground level and put a cap on it? Then open the cap for venting when dumping but otherwise leave the system closed? Or just go ahead, extend it and make it a permanent vent?

Since you aren't going to be using it daily, a dose of some brand of bacteria every now and then, would also be helpful, Bio Clean , Robic, etc.

Good idea!

Thanks everyone for the feedback so far!

 

[Bird]

Just for your information in case you don't already know it . . . Lots of RVers put chemicals in their holding tanks to help break down solids and prevent odors. Places that sell RV supplies and accessories have chemicals specifically for that purpose. Some (not all) of those chemicals will kill the anaerobic bacteria. In other words, they stop the normal functioning of a septic system. So first, if you use such chemicals, try to get ones that won't do that, and second, consider adding bacteria, as recommended by Kays Supply.

And if I'm telling you something you already know, sorry about that.

 

[charlz]

Just for your information in case you don't already know it . . . Lots of RVers put chemicals in their holding tanks to help break down solids and prevent odors. Places that sell RV supplies and accessories have chemicals specifically for that purpose. Some (not all) of those chemicals will kill the anaerobic bacteria. In other words, they stop the normal functioning of a septic system. So first, if you use such chemicals, try to get ones that won't do that, and second, consider adding bacteria, as recommended by Kays Supply.

And if I'm telling you something you already know, sorry about that.

I have read lots of 'black tank' posts over on RV.net but no worries on mentioning it here I plan on using the 'natural odor control' additives which I believe are just a large dose of the good bacteria. Need to double-check that and select a product to buy. The formaldehyde products are supposed to be much better at odor control but those are the ones that kill off the bacteria and are bad for septic systems. We will see how it goes.

 

[Gale Hawkins]

Doing this does not require any "overthinking" of the issue. Just do what you stated in the first post.

We use the cheap bacteria stuff (like we use for the septic tank at home) from the Dollar General to start to predigest the stuff when on the road by putting it into the black tank before we leave the house in about a gallon of water so the tank is not dry on the bottom at first usage.

Beware www.rv.net is like any other forum. Only about 10% of what you read is valid. If you know the 90% not to read you will be just fine.

 

[Patriotic Stabilist]

I'm lucky that our duplex is on city sewer and we had made a cleanout toward the front. Never thought about a motorhome at that time but it will be an ideal place to dump the tanks.