Grey Water Tank Overflow Help

tombeaux

We took delivery of our 2018 320S in January and have been very pleased. We have used it on four outings, the last one for nearly two weeks. TV is a 2017 Toyota Highlander XLE with AWD (5,000-pound towing capacity with the AWD). Everything has worked well and thanks to reading this forum and the Facebook T@B forum (and a thorough walk-through from our dealer, Princess Craft), the learning curve was not that steep. On our last trip, we noticed our grey water tank was at 94 percent full. At that point, we were about 12 hours from leaving and hitting the dump station. We just tried not to let anything else go down the sink and did not shower. We had no issues and use the toilet several times that evening and the next morning. Then, as we were packing up, we noticed a small amount of water on the shower/toilet floor. We assume that grey water had backed up onto the shower floor, right? It was obvious (to us) that it was not from the black water tank because that would not have come up through the shower drain, plus there was no odor. 

My question for those who know - why would we experience no backup overnight, yet have it appear even though no more water had been added to the grey tank. Any ideas what's going on here?

Side note - for those thinking about the indoor bathroom, it has worked out great for us. I was a little concerned, but it has been very handy in the middle of the night. The dump station trips are a non-event. It is a really easy process with virtually no foul odors, no spills and no direct contact with anything unpleasant.

George101

Was the "overflow" noticed after hooking up your tow vehicle?   If so, its probably just related to changing the level of the tab.

pthomas745

Wild guesses: temperature changes in the weather?

HR_Taly

Even though I am always particular about leveling, if I'm even a small amount off I know my tank will vary as to what will truly be full.  Right now, if I go beyond 75% grey water will come up through the shower drain (I'm a good click off from being level front to back... I don't notice it, but my tanks do! Don't ask me how I know... ugh!).

I'd say that as you walk in your T@B, or as you may get things out of the front box or move stuff around inside, this will re-distribute the weight and the water level may slosh or rise up. Also, your stabilisers may sink into the ground as it gets more compact causing a slight level change that you wouldn't notice, but your tank might.

Like you said - luckily it's grey water and luckily it just goes into the shower pan!

tombeaux

The leveling or jostling might have been an issue, especially with the tank on the verge of full. More detail - I got up early to go trout fishing and returned about 9:30 a.m. My wife had used the toilet earlier (but after I went fishing) and there was no water there. However, she was starting to pull stuff together for us to leave. It is possible that the activity might have jostled the T@B enough to create some sloshing action. Makes sense. I know we will be more diligent about monitoring that tank level.

ChrisandAlexis

@tombeaux, we learned on our first trip that when we hit 80% on the grey water SeaLevel readout that the water came up through the shower drain. Before we went on our second trip we got a 6 gallon portable tank to empty into when the grey water reading got to 50%. Then I would just go to the dump station at the place we were staying at and empty it. This process would allow us to stay a couple of days and not worry about water coming up through the drain again.

HR_Taly

@tombeaux, I do exactly what @ChrisandAlexis mentioned.  I boondock nearly exclusively and I have one of these caps on my grey tank outlet. 
It allows me to hook up a normal garden hose to the drain outlet.  I often drain my grey tank (I don't have a black tank) into portable containers and then take those to a dump area.  The grey tank is only 19 gallons, so even taking two or three gallons out of it reduces the level a good bit.  These caps are really inexpensive and so handy!

Dalehelman

Probably just a bubble that shifted in the GW tank overnight.

ericnliz

  Kinda like a "smart fart" @Dalehelman?

teardroptraveler

My family has a 2017 T@B Outback and my husband and I just finished our second trip.  We’ve experienced issues with water backing up and filling the shower pan even upon arrival when we’ve only run the water a short period and taken one quick shower (no flushing and black water tank is on 0%).  The grey water drains only at a trickle and we could only get it to lower to 69% before we just had to leave the campground to travel home.  I assume maybe there is a blockage, but that seems strange considering it was a brand new RV when we got it and it’s only been used 5 nights in the last year.  Any tips or suggestions? We otherwise love it! 

Sharon_is_SAM

Sounds like you have a blockage of the dual gray water/black water air vent preventing you from completely filling your tank or emptying it.  The vent is in the front driver side corner and I would try flushing the vent.  A seasoned modder here on the forum actually rigged the vent to be used to flush his black tank, so water should not hurt it.  @Dalehelman, can you chime in please?

atlasb

We carry several 5 gallon buckets with Gamma seal lids for the purpose of emptying the gray tank.  After running the water at hook up to get all the air out and having 2 showers the first night , I like to empty about 8 to 10 gallons of gray water.  The buckets work great for this as I find a point in our campspot lower than the drain and use the black flush hose to drain.  We find that we try not to let the gray tank get above about 2/3 full.  Some Corp of eng sights allow you to dump gray water with a hose at your spot.  We do have the 2018 400 T@B.  We do carry a separate garden hose for the black water flush. and also use for the drain of gray water while set up.