Which gray tank to dump first?

[Hpangle]

This is our 4th 5th wheel but the first one with two gray tanks. Now after the Black is drained & flushed, which gray tank should be drained? Shower one or kitchen sink one? I can come up with good reasoning for either one to be first, and would like to hear from those with experience in this area. In doing a search of this topic, I found a post with a drawing of the three tanks, and that almost leads me to believe the shower should be drained after the black tank? Thanks for your inputs.

[JCR GD]

I always do the kitchen first (after the black) and shower second so any little food particles that are in the kitchen tank will continue on down the common drain line with all the shower water.

[Calbar]

This is our 4th 5th wheel but the first one with two gray tanks. Now after the Black is drained & flushed, which gray tank should be drained? Shower one or kitchen sink one? I can come up with good reasoning for either one to be first, and would like to hear from those with experience in this area. In doing a search of this topic, I found a post with a drawing of the three tanks, and that almost leads me to believe the shower should be drained after the black tank? Thanks for your inputs.

^^^^^^ I do the same as Hpangle. Dirtiest to cleanest.

Rob

[boyscout]

This is our 4th 5th wheel but the first one with two gray tanks. Now after the Black is drained & flushed, which gray tank should be drained? Shower one or kitchen sink one? I can come up with good reasoning for either one to be first, and would like to hear from those with experience in this area. In doing a search of this topic, I found a post with a drawing of the three tanks, and that almost leads me to believe the shower should be drained after the black tank? Thanks for your inputs.

I figgered I was an odd one to be weighing this question. Apparently not. However I've done all my wondering while I'm standing there dumping the tanks, not at 2:07AM!!

After much "experience" but absolutely no expertise I dump the kitchen first, then the bathroom, on the logic that there are more bits and oils in the kitchen tank that will subsequently be flushed from the post-valve manifold and pipe-work of the dump system by the cleaner bathroom waste. I use the GEO method, so often have lots of water softener and Dawn dish soap in both tanks.

However any notion that the bathroom tank had relatively clean waste in it was dispelled recently when I was deliberately filling the tank to maximum to get a good rush out of it on dumping. As the tank neared full it gave a great belch out of the sink drain and OMG the smell could be weaponized! Apparently the stuff I wash off myself isn't as sweet as I thought it was.

So, case closed. Drain the kitchen tank first, and get some sleep!

[Bamaman]

We always are on city water on our Reflection.

I just dump both gray water valves together at the same time. Bigger flush through the pipe is better than a lesser flush.

I also often will close the gray water valves the morning we leave, and let water build up in the gray water tanks before opening the valves.

[Skiddy]

We always are on city water on our Reflection.

I just dump both gray water valves together at the same time. Bigger flush through the pipe is better than a lesser flush.

I also often will close the gray water valves the morning we leave, and let water build up in the gray water tanks before opening the valves.

I do likewise. The kitchen gray has a street elbow, so either or both can be open at once it will drain before it backs up. My kitchen gray is a long gentle slope so I do open it first to get things moving before walking back and opening Grey 2. If still on city water, open both kitchen and bath taps (water heater off).

[boyscout]

I just dump both gray water valves together at the same time. Bigger flush through the pipe is better than a lesser flush. I also often will close the gray water valves the morning we leave, and let water build up in the gray water tanks before opening the valves.

I do likewise.

There are YouTube videos simulating the dumping of tanks with waste in them, might be worth watching. Even when a full tank is dumped, a surprising amount of stuff is left behind in the tank. When the tank is less than full there is even less movement of the bits and chunks in it.

Leaving grey tanks open while camping so that the liquid drains out but most of the solids remain in the tank is likely to build up a layer of thoroughly-attached bits and chunks in the grey tank (kitchen especially, of course). This will increasingly retain more of the bits and chunks, and will eventually lead to problems draining the tank. It's better, as much as possible, to dump all tanks when full and not with just a morning's worth of waste in them. The water building up in the tank over days keeps the bits and chunks less-attached to each other and to the tank, and the outward rush of extra pressure when dumping that full or nearly-full tank carries bits and chunks out with it in a way that lesser flows do not.

The second chapter of this un-requested advice is that when pulling both gray handles at once you're sending both greys into one 4" outlet pipe and thereby constricting the flows out of the tanks. While flushing the post-valve outlet system with maximum pressure is certainly a good thing, it comes at the likely expense of leaving more stuff in the tanks themselves because the flow out of them has been reduced by the constriction of the single post-valve outlet handling outflow from two tanks at the same time.

[Bamaman]

When going for a week or longer, I often hook up two water hoses with on/off valves. One hose goes for a black water flush.

Maybe I need to tell everyone to go to the bathhouse.

[Skiddy]

At home we leave the bits and chunks on dishes, the dishwasher manufacturer says it is oK and the sensors will adjust accordingly. When in the RV, we do wipe dishes and skillets with a paper towel to get as much oil and virtually all the food bits and chunks off before the dishes even go into the sink.

As boyscout says, the bits and chunks will remain in the tank, best to not let them get into the tank in the first place.