Leaving Grey Drain Open at Camp?

silverta16 · 10-01-2018, 01:32 PM

My new to me 184BH, camping this weekend with full hookups left the grey valve open for the girls endless showers. Horrible odor came up from the kitchen sink and shower drains. I assumed a Pea trap should prevent this. Do I have a problem or is this something that can happen? Do you leave your grey drains open or just dump when needed? I guess maybe my neighbors were pushing harder than I was LOL.

Grumpy · 10-01-2018, 01:44 PM

Always left GW valves open when connected to sewer never once had an odor issue over a 41 yr span.

Fr8Train · 10-01-2018, 01:48 PM

Quote:

Originally Posted by silverta16

My new to me 184BH, camping this weekend with full hookups left the grey valve open for the girls endless showers. Horrible odor came up from the kitchen sink and shower drains. I assumed a Pea trap should prevent this. Do I have a problem or is this something that can happen? Do you leave your grey drains open or just dump when needed? I guess maybe my neighbors were pushing harder than I was LOL.

P-traps only work with water in them. Many newer campers don’t use them. Instead they opt for an in pipe “one-way” seal. They work when clean but can let odors in if they are cracked open a bit.

Was the smell the campground sewer or your own gray tank? You can make your own p-trap with the sewer hose to help keep the sewer gassed out of your system

oldmanAZ · 10-01-2018, 01:57 PM

I never had an odor problem and leave the black and grey valves CLOSED. I dump the black tank first and then have water in the grey tank to clean the really bad stuff out of the sewer hose with the grey water.

Regarding the odor...
- If there is sufficient air pressure difference with the grey dump valve open, it seems possible that air from the septic tank/sewer system could enter the grey tank and bubble past the water 'seal' in the P-trap and into the trailer.
- Something else to consider, if the trailer has an exhaust fan running and air is being exhausted, then every time the toilet is flushed black tank odor could be sucked into the trailer.

Marcm157 · 10-01-2018, 02:00 PM

I don't like leaving either valve open. I'd rather dump grey as often as necessary. Just my opinion but with the valve open there is basically nothing between the sewer and your camper. I get the whole purpose of the P Trap but again, I'd rather leave the valves closed and dump as necessary.

Robbbyr · 10-01-2018, 02:01 PM

On my Seneca I found that both of my installed "air admittance valves" (which assist with venting) were both very cheap and had stuck flappers. Noticed by the the same method you did, worsened when an exhaust fan was running. Replaced both with models from Home Depot and problem solved.

Be aware driving may empty your traps (bouncing around) so run a bit of water in each when set up to eliminate that possible source. Even though I replaced my AAVs I now usually create a trap in my sewer hose since I leave my grey valve open, I have an onboard laundry. Makes grey fill fast!

spoon059 · 10-01-2018, 02:02 PM

I leave valves closed unless I am actively dumping them. No smells, no worries, no problems.

2edgesword · 10-01-2018, 02:56 PM

I always keep mine closed so I'd try closing the gray tank valve and see if that remedies the problem. For me having to open the valve every other day to drain the gray tank is preferred over having the smell in the RV.

GABob · 10-01-2018, 04:28 PM

Just make sure all your girls are all familiar with the differences between RV utilities and those at home.. Was out last week and had the oldest join us, and it was her first time in the RV. After she went home, my youngest came to me complaining that the bathroom wasn't as pleasant as before. So, as I go to investigate I quickly noticed a tolerance stack up issue. There is a small pipe at the bottom of the opening that has an outside connection to help flush the black tank, and it does a great job. However, in this case it contributed to the tolerance stack up, needless to say. Thank our lucky stars that my sister-in-law gave my daughter some s'mores sticks for our trip, which happen to be the perfect length for resolving the issue.

RV'ing really helps to bring out the creative genius in you

Kim Gass · 10-01-2018, 04:28 PM

Quote:

Originally Posted by spoon059

I leave valves closed unless I am actively dumping them. No smells, no worries, no problems.

us too

Too many CG sewers are poorly designed and odors come up through them.
Next time if you dare. before hooking up open the sewer connection on the ground. you might find the fault is not yours
When the gray water fills you will notice overfill coming up in the tub and a noise called eek if there is a user
At that point open the grey water valve

**Midnightmoon** · 10-01-2018, 04:51 PM

This topic comes up from time to time on this forum and there are 2 distinct camps as far as what we do. Neither are right or wrong, just 2 differing opinions.

I'm from the leave the valve open group. Never an issue over many, many years of doing the same.

Fyrehuntr · 10-01-2018, 06:24 PM

I have left my grey tank valve open with no issues. After reading this article, I think I will start keeping it closed until I need to empty.

https://rvtravel.com/good-or-bad-ide...e-as-a-p-trap/

Fr8Train · 10-01-2018, 06:39 PM

The article gives only opinion and offers no facts. IMO

Scott_Trailer_Newbe · 10-01-2018, 07:06 PM

Haven’t read every post, but I would prefer to let the grey build just like the black. This way you can flush the black water out of the hose after dumping. Grey should always be last.

michael.g · 10-02-2018, 06:42 AM

Short term camping, we leave both closed and dump as necessary. The last few years we have been seasonal camping and leave the grey tanks (we have 2) open all the time until it is time to winterize. With the 4 of us, we'd be dumping the grey tank on an almost daily basis.

We have never had an issue with odors coming from the grey tank. Have left the grey tank open for 4 - 5 months at a time on our current TT and our previous MH. No problems. At our seasonal site, we have our own septic system.

-Michael

travelingjw · 10-02-2018, 07:30 AM

I always keep my valves closed. When someone showers, we empty the grey tank that day. If you have ever smelled the sewer when connecting, why leave an open airway to your TT. In addition, if there is ever a back-up or back flow from the sewer, closed valves protect your TT.

rkresge · 10-02-2018, 07:40 AM

Quote:

Originally Posted by silverta16

My new to me 184BH, camping this weekend with full hookups left the grey valve open for the girls endless showers. Horrible odor came up from the kitchen sink and shower drains. I assumed a Pea trap should prevent this. Do I have a problem or is this something that can happen? Do you leave your grey drains open or just dump when needed? I guess maybe my neighbors were pushing harder than I was LOL.

My vote is don't leave the grey water valve open it. However, if you feel you need it, open it for the duration of the showers. Think about this: With the valve open, you're open to whatever may decide to come in though your hose. Critters, smells, etc.

But it's up to you. Many people do leave the grey tank valve open.

Enjoy your camping!

Roger

hbravo · 10-02-2018, 07:54 AM

When I’ve felt the need to leave the gray open I’ve had good luck leaving a big droop in the waste hose that, if correctly positioned, will for its own p-trap. I do put the hose back on the support before I drain the black tank.

Periodically I also put black tank packets in my gray tank. I think that helps to eliminate residual stink like it does in the black.

tom463219 · 10-02-2018, 08:04 AM

I used to keep the grey valve open too. Then I saw this. Doug Swarts of Drainmaster.com says keep both dump valves closed. Prevents sewer rats and sewer flies from getting into your tanks.

https://youtu.be/Q4A-41EdBBc

tjpolsin · 10-02-2018, 08:42 AM

Keep them closed unless dumping.
Solids do end up in your GW tank (food particles, dirt, soap, etc). By leaving the GW valve open, those solids will accumulated on the bottom of the tank. Waiting until the tank is full will allow the high flow of water to flush out at least some of those solids.

As for odor, try disolving one or two BW tank deodorizing packets in your sink and flushing them into the tank. Drop them in before you head out from home, leave your valves shut while camping, then dump before you leave.

then put new packets in both tanks for the trip home. They will keep the smell down, and continue to breakdown any solids left.

Tim

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