I'm 3500 miles into my 6000 mile trip with my new TT. We've been doing a combo of boondocking and campgrounds. When boondocking, one gray tank fills but the other stays empty.... What am I doing wrong? Is there a switch/valve/anything? This is my first TT with dual gray tanks. Any help is appreciated!

I believe on some units one tank is filled by the shower/bath sink.The other tank is filled by the kitchen sink.Or some similar setup.Could it be you're not using one sink often enough to fill the second tank?Maybe I'm totally wrong and there's a valve you're missing.

Some rigs have the galley on one grey tank, the bath and or shower on another. Are you using all of the facilities in the rig?If you are going by the monitor gauge, forget it and dump. They are not very accurate or may not even be working.

We have two gray tanks; one for the kitchen sink and the other for the bathroom sink and shower. The latter fills up in 3 - 4 days with two adults and only one using the shower. The kitchen goes on seemingly forever. One trick is to leave both tank valves open and let the levels balance. We have a valve on the sewer outlet that prevents leakage when we do that balancing.

Brochure only shows 38 gallon 'waste' tank and a 38 gallon 'grey' tank.Photos only show 2 dump valves sticking out by drain line.Floorplan shows kitchen sink (mid trailer....curbside) and a bathroom (rear roadside) with shower/sink/toilet.Would think 'waste' tank is rear bathroom and 'grey' tank is kitchen sinkSo.....Why do you think you have dual grey tanks?How many tanks on level monitor?How many drain valves?

I suspect you have one gray tank and one black tank. The gray tank is for kitchen and shower.The black tank is from the toilet. Probably the black tank is empty, or near so, but that depends on whether you are taking showers in the trailer or using the campground facilities.

Gray tanks question | Good Sam Community

22 Replies

beermanjoe
Explorer
Jul 07, 2015
My 2015 Keystone has 2 monitors with 1 Grey Tank.
WE3ZS
Explorer II
Jul 06, 2015
Sounds like the OP has resolved his question with it only having one grey tank and a monitor that has the ability to monitor 2 grey tanks.
Our TT has 2 grey tanks (and a matching monitor panel) but the forward of the two tanks is solely for the washer/dryer prep package and has never had a drop of water in it. The rear grey tank takes the water from the kitchen, bathroom sink and shower. If we ever do much boondocking I will get an externally mounted valve on the sewer outlet that will allow for the two grey tanks to be floated together to double our capacity.
dee74
Explorer
Jul 06, 2015
Old-Biscuit wrote:
dee74 wrote:
My tt has two tanks and two valves. One tank holds the kitchen and bathroom sinks and the other tank is only the shower. The specs for my tt say I have one 74 gallon grey tank but there are definitely two tanks. I am not sure how big the tanks are but I an thinking they are 74 gallons each. We as a family of three can go 4 days without emptying and we are not trying to conserve water. We only pause the show in between rinses to conserve hot water.

Where does the toilet go?

The toilet has a separate 40 gallon black tank. I have two gray tanks both with separate dump handles and one black tank with a separate larger dump valve. ,
Old-Biscuit
Explorer III
Jul 05, 2015
dee74 wrote:
My tt has two tanks and two valves. One tank holds the kitchen and bathroom sinks and the other tank is only the shower. The specs for my tt say I have one 74 gallon grey tank but there are definitely two tanks. I am not sure how big the tanks are but I an thinking they are 74 gallons each. We as a family of three can go 4 days without emptying and we are not trying to conserve water. We only pause the show in between rinses to conserve hot water.

Where does the toilet go?
dee74
Explorer
Jul 05, 2015
My tt has two tanks and two valves. One tank holds the kitchen and bathroom sinks and the other tank is only the shower. The specs for my tt say I have one 74 gallon grey tank but there are definitely two tanks. I am not sure how big the tanks are but I an thinking they are 74 gallons each. We as a family of three can go 4 days without emptying and we are not trying to conserve water. We only pause the show in between rinses to conserve hot water.
lanerd
Explorer II
Jul 05, 2015
Our old 25' rear kitchen TT had two gray tanks. The shower/sink tank drain valve was located with the black tank drain valve, but the kitchen sink gray tank valve was located at the far end of the trailer. At public dump sites, I always had to dump the bath gray/black tank first and then pull forward about 15' to drain the kitchen gray tank.

So my point is, look else where for the kitchen gray tank dump valve.

Ron
4X4Dodger
Explorer II
Jul 05, 2015
Fastest way to resolve this is to call the factory with your VIN number. They will be able to tell you in 5 minutes what the deal is.

The VIN will include any options not shown on the brochure.
2112
Explorer II
Jul 05, 2015
dhust wrote:
My TT has 2 grey tank indicators on the monitor, but only 1 grey tank.
Same here. If you have only one gray drain valve you have only one tank.

I had a previous TT with a galley tank and its valve handle was located between the street side tires.
enblethen
Nomad
Jul 05, 2015
Owner's manuals are written for many different models so it is not the best guide.
Anmacc2
Explorer
Jul 05, 2015
Definitely only only one gray valve.... I'm thinking one tank. Maybe leaving the owners manual home to save space and weight wasn't my best idea. LOL
Thank you everyone!