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Old 04-01-2018, 10:44 PM   #15
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Originally Posted by JFXG View Post
A lot of people overreact to stories. Consider that story told to keger. A motorhome flooded to overflowing with sewage because their gray valve was left open when a CG sewer backed up. Think this through— a sewer line or septic tank is at least 2-3 ft underground, often more. The floor of an RV is another couple of feet above ground, and the bathtub/shower rim (which any backup would have to overflow) another foot above the floor. That means that any CG backup would have to have enough head pressure— coming from somewhere, not just other RVs running water— to force tank sewage up more than five feet above tank level. Highly unlikely.

With washing and other utility uses, the gray tank will always fill far more quickly than the black. Rather than drain the gray every day or two, far simpler to just run it open and then close it a day before emptying the Black. The gray will fill up, and after the black drain, will give a thorough flush to the interior gray tank and all the sewer valves and lines. This periodic flush will also serve to prevent the establishment of the flies. That is my personal experience of six years fulltiming, not a story some guy in a campground told me.
I'm with jfxg. More internet stories. Even if there were enough head pressure to lift sewage 5 feet or so, it would have to not blow off every drain elbow going into the system at every site.
Won't ever happen.
I leave the grey valve open all the time and close the day prior to draining the black tank also. Never had a problem with sewer smells. Ever. In 18 years.
Originally Posted by keger View Post
Can't really answer your question but I talked to a guy who left his gray water valve open while camping. Him and the wife left the MH for a day of shopping when they came back sewage was pouring out of there MH. Here the CG sewer backed up and forced that crap (no pun intended) into there MH with the open valve. I think there still cleaning out the smell. After hearing this story I never leave any open valves on my MH. Just a word to the wise.
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Old 04-02-2018, 07:35 AM   #16
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Here's and interesting video on this subject.

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Old 04-02-2018, 11:34 AM   #17
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Well, today was a successful day since I learned something new. The video makes sense and from now on I will keep the gray tank closed during my extended stays.
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Old 04-02-2018, 11:51 AM   #18
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Wow, I hope I don't get a sewer alligator in my gray tank.

The benefit of full hookup is to be able to take 2 long showers and do the morning dishs without filling the shower pan with dish water.

If there is a sewer hookup, mine stays open.
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Old 04-02-2018, 12:02 PM   #19
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Yup, the video did it for me too. This place is wonderful!
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Old 04-02-2018, 02:12 PM   #20
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One day a couple years before we got our coach and were still in our S&B, I heard DW let out a terrified shriek from the bathroom. I came running in and she said that she heard some splashing in the toilet then something bumped her butt while she was doing her business. I looked and there was a large toad in the toilet and he was anxious to get out! Apparently it had fallen into an open vent in the septic system outside and made its way up and into the toilet. If that can happen in a residential septic system, it could happen in a RV park. If a toad can do it, I can only imagine what else could. DW has left zero doubt that both tank valves will remain closed until and unless opened to flush the tanks.
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Old 04-02-2018, 02:16 PM   #21
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The part of the video that changed my mind was our sewer connection, gray tank and roof vent ends up being the venting for the entire park sewer system.

Thinking back I have sat outside in the morning drink my morning coffee and sometimes get a strong sewer smell and now I wondering if that was the campgrounds sewer system venting through my roof vent.
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Old 04-02-2018, 02:37 PM   #22
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In the eighties I started finding roaches periodically in my Rv while staying at a park for about 6 months. I read an article in the paper that said the county was gassing the sewer system to kill roach infestations. I think they were chased into any safe place ( my grey tank ) and then got through my traps. I started keeping grey valve closed after that and never had even one more.
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Old 04-02-2018, 07:20 PM   #23
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Originally Posted by CWSWine View Post
I was talking with a fellow camper and he said if you leave you gray tank valve open you should make a "U" or P-Trap out of your sewer hose to prevent smell and flyes from entering you gray tank from the campgrounds sewer system. Any truth to this?

Yes, but smells should go up your grey vent.
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Old 04-02-2018, 07:32 PM   #24
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I keep both valves open when sewer hookup is available (10 months of the year) and haven't had any problems in 6 years of full timing. It works for me, but I do take some precautions like lot's of water, no toilet paper in tank and add soap with 2-3 gallons of water to slosh around on travel days.
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Old 04-02-2018, 08:25 PM   #25
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Just how is one supposed to physically create and support a P-trap in a 4" stinky slinky hose - one that would maintain a water sealed separation?
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