Converting Bath Sink to drain to Black Tank versus Gray Tank

[dkoldman]

Below is a Mod I would love to make. In 4 years, we have learned we generate gray water 2 to 1 to black water. So what I want is to have a valve on my bath room sink where I can divert the bath sink water to Black or Gray tank. If a valve is not possible, I would accept it permanently being plumbed to Black tank. I am convinced that the change would have us using generating Black & Gray equally.

Note:
Freshwater is 70 gallons capacity
Gray is 61 gallons capacity
Black is 40 gallons capacity

So when Gray shows 2/3rds Full; I have at least 40 gallons of Gray water, similarly when black tank is 1/3rd Full, I have at least 12 gallons.

Any ideas on the plumbing or other option to maximize the available space in Black tank?

[dkoldman]

Originally Posted by l1v3fr33ord1

dkoldman-

Fresh and drain water piping drawings are available for 2019 coaches here.

I understand that older coaches (perhaps pre-1995) may have a single tank for grey and black water. I've read that some folks with newer, separate-tank coaches simulate this by opening the grey and black tank dump valves at the same time, with the dump pipe closed off (by cap or separate valve). As most folks use more grey water than black, this "balancing" usually means grey water flowing into the black tank. It's a purely manual process, as opposed to a grey water forwarding pump or replumbing a grey water source into the black tank. May be worth trying to see if this works well enough for you, before making permanent changes.

If your coach has a black tank flush, and you use it, be careful what you replumb into the black tank. A backup through the black tank vent and toilet is one thing (and may be limited in damage if you don't open the toilet ball valve), but a backup of black tank contents into the sinks may be more than you can handle!

Wow, this reminds me of being in Redwood National Forest and not seeing the forest due to all the trees

I actually open gray and black tanks valves when I am dumping the black tank. It is same theory as more volume is in gray it pushes into the black to help clean the black.

But if I follow your suggestion, I could actually wait until next time my gray is 2/3rds full and Black is 1/3 full. That would be 53 gallons total and if all things are equal based on where tank is located, I would have about 26 gallons in each tank. The Gray would drop from 66% to 42% capacity or showing 1/3rd Full. The Black tank would rise from 13% to 65% right at 2/3rd full. If I could somehow reclose the valves, I could still use at my normal usage rates and Gray would fill BEFORE the Black tank. This may work except for one big problem. When I open the main central valve from the waste tanks, the gray and black waste would flow out ( at least the waste that is behind the holding tanks and inside the main central cap that both drains flow through

[l1v3fr33ord1]

dkoldman-

The plumbing diagram (link here) appears to show individual waste valves for both the grey and black water tanks. Same for the operator's manual (link here), page 7-9. I don't see a "main central valve." So, I'm a bit confused. Does your coach have a valve in addition to the ones shown?

I think I understand your question to be: "How do I handle the mixed grey and black water that accumulates downstream of the drain valves? If I let it build up behind the drain cap I'll get a 'surprise' when I remove the cap to dump the tanks." One "solution" is to add a twist-on valve where the cap goes, and then apply the cap to the outlet side of the valve. Here's a link to a Valterra twist-on valve, model T58. A picture is below.

[bigb]

Someone here recently did something similar to what you want by using a pump to move gray into black. They already had a gray pump so just needed to add a hose or something. I have a gray pump as well and have considered adding a wye and a valve but the need has not been that great so I've not done anything. Theoretically I could permanently change my gray pump to go to the black tank all the time because I added a separate gray drain and I don't use the pump anymore to empty gray.

edit: looking back I see it was you and you are now looking for a more permanent solution.

[creativepart]

There are Winnebago RVs where some fixtures, other than toilets, were factory designed to empty into the black tank. I know this because we’ve had people here complaining about how their black tank was always filling up too fast and they wanted to change the setup.

Since it is so much easier to deal with gray water than black water I would not want anything that would fill the black tank faster.

Have you tried putting a plastic dish pan in the bathroom sink and then dumping its contents into the toilet?

The easy answer is a RV Tote Tank for hauling gray water to a dump site.

[Marine359]

We use a tote to haul away gray water in the bed of our truck. To do that, we use a 12v transfer pump (with hose dedicated for this) to pump the gray uphill into the truck bed. There’s no reason you couldn’t use the same pump/hose to transfer gray water into black tank through the toilet. A bit more hassle going through a window with the hose, but much less expensive and complicated than adding a valve and punching another hole in the black tank.

[powercat_ras]

Take some non-destructive steps...

Reduce grey water generation such as Oxygenics shower head and a way to preheat the water to the shower head without running it down the shower drain. You can also catch the cold water running out of the shower head in a wide mouth container and then use it to fill the toilet after flushes as a way to reduce grey and increase black tank use. Even a winshield washer jug or milk jug with the top cut off is big enough for this.

and or ...

You could get a bigger wide mouth container like this from Amazon, and use it when needed to drain some grey water and and then carry it inside and pour it down the toilet. But it is another big bulky thing to lug around and find some place to carry in your RV.

[dkoldman]

Originally Posted by l1v3fr33ord1

dkoldman-

The plumbing diagram (link here) appears to show individual waste valves for both the grey and black water tanks. Same for the operator's manual (link here), page 7-9. I don't see a "main central valve." So, I'm a bit confused. Does your coach have a valve in addition to the ones shown?

I think I understand your question to be: "How do I handle the mixed grey and black water that accumulates downstream of the drain valves? If I let it build up behind the drain cap I'll get a 'surprise' when I remove the cap to dump the tanks." One "solution" is to add a twist-on valve where the cap goes, and then apply the cap to the outlet side of the valve. Here's a link to a Valterra twist-on valve, model T58. A picture is below.

The plumbing diagram Page 3 seems as if it is reversed or backwards?

It is not a main central valve, I also called it a main central cap. I didn't know formal name so I was trying to say the main release point that we can open / close several ways.

We have a v2 model of our coach so your pictures may not be 100% correct in the manual. i.e. the pdf manual you reference says the Sink Drain switch outside can be turned ON/OFF but in our model in our manual it says press and hold.

The same manual also says to never open Gray & Black tank valves at the same time

I like the twist off valve.

I am gonna study some more about opening both tanks as it may resolve my primary issue. I may need to do some testing with fresh water.

[dkoldman]

Originally Posted by powercat_ras

Take some non-destructive steps...

Reduce grey water generation such as Oxygenics shower head and a way to preheat the water to the shower head without running it down the shower drain. You can also catch the cold water running out of the shower head in a wide mouth container and then use it to fill the toilet after flushes as a way to reduce grey and increase black tank use. Even a winshield washer jug or milk jug with the top cut off is big enough for this.

and or ...

You could get a bigger wide mouth container like this from Amazon, and use it when needed to drain some grey water and and then carry it inside and pour it down the toilet. But it is another big bulky thing to lug around and find some place to carry in your RV.

I am 99% sure our Fresh water bandit is the washing of our hands. It is a habit that we don't really want to break. Also, we never run out of fresh water, or go on Full with the gray tank. But if the bath sink wastewater would flow into black tank, I think we could go twice as long and as yes to the point where we may actually run out of freshwater. As it is, I am always dumping black tank with 15 gallons or less plus the thetford chemicals going to waste.

[Marine359]

Another tactic is to wash dishes in a plastic basin. When done washing, pour soapy water into toilet. Then go back and rinse dishes in empty basin. Then dump rinse water into toilet. Think of catching all galley sink water before it goes down drain and emptying it into toilet. And, yes, as Randy mentioned, Oxygenics shower head saves a lot of water. Just make sure you’re taking Navy showers, shutting off water while soaping up, and rinsing off. Showers should be done using less than 5 gal. Wash/rinse dishes/pots/utensils 2 gal. Switching to paper plates while boondocking helps too.

[dkoldman]

Originally Posted by Marine359

Another tactic is to wash dishes in a plastic basin. When done washing, pour soapy water into toilet. Then go back and rinse dishes in empty basin. Then dump rinse water into toilet. Think of catching all galley sink water before it goes down drain and emptying it into toilet. And, yes, as Randy mentioned, Oxygenics shower head saves a lot of water. Just make sure you’re taking Navy showers, shutting off water while soaping up, and rinsing off. Showers should be done using less than 5 gal. Wash/rinse dishes/pots/utensils 2 gal. Switching to paper plates while boondocking helps too.

Thanks, all good ideas. I have another mod where if it works... it will make it easier to wash dishes using outside kitchen sink. The current momentary switch is just an impediment to productivity.

We don't have an issue with water capacity. We have gone a full week on one tank (70 gal) Our problem is the Gray will full 1st. That is not a problem by itself, but if the Black tank is still sitting at 1/3rd tank; thus the opportunity.

I am sure my wife will not want to carry water from indoor kitchen to toilet, but she may use the outdoor kitchen sink more if it is easier to use.

Note: I am not trying to have equal amounts of black / gray waste water, but trying to find a balance of fill ratios for both of the holding tanks the way we use the RV. A drain diverter on Bath sink to use either or seems like a no brainer, but I acknowledge adding one after the fact may be a stretch.

[dkoldman]

Originally Posted by bigb

Someone here recently did something similar to what you want by using a pump to move gray into black. They already had a gray pump so just needed to add a hose or something. I have a gray pump as well and have considered adding a wye and a valve but the need has not been that great so I've not done anything. Theoretically I could permanently change my gray pump to go to the black tank all the time because I added a separate gray drain and I don't use the pump anymore to empty gray.

edit: looking back I see it was you and you are now looking for a more permanent solution.

You are correct, this has bothered me for a while now.

I have a portable Flo Jet Macerator pump that I keep in the wet bay. I use it mainly to dump both tanks while at home, but I have 25' orange hose that I can route through a window or even the front door and dump gray into black tank. It works I even tried to pump the gray into black using the Sani Fil port, and while technically it worked, I will not recommend because it clogs the strainer in the Sani Fill. I will no longer do that

[dkoldman]

Originally Posted by creativepart

There are Winnebago RVs where some fixtures, other than toilets, were factory designed to empty into the black tank. I know this because we’ve had people here complaining about how their black tank was always filling up too fast and they wanted to change the setup.

Since it is so much easier to deal with gray water than black water I would not want anything that would fill the black tank faster.

Have you tried putting a plastic dish pan in the bathroom sink and then dumping its contents into the toilet?

No, but this has a lot of merit

The easy answer is a RV Tote Tank for hauling gray water to a dump site.

At least WBGO plumbed the Outdoor sink to the black tank, but to nullify that wisdom, they switched to a momentary switch n v2 of our Year model. Using the outdoor sink is a PITA and requires cleaning after each use trying to coordinate the water and the drain pump. If drain pump can stay on while both hands are free our results may change. On our last trip, my wife held the switch while I cleaned items from the grill.

If I were able to divert bath sink to black tank, I would prefer to have it connected with a valve so you could have the flexibility to choose what you need. Our black tank is never close to being full. I know that is a good thing, but if my Gray is full, I have to dump it. While I am set up for dumping, I might as well dump the black even though it may only be 15-20 gals.

But all of the above aside, if we can find a small portable wash basin that fits into the sink, that may be the ticket We could use when washing our hands, brushing our teeth etc. It would have portability so we could flex based on actual tank volume. It is tiny sink as it is, but this is very good idea

[dkoldman]

Originally Posted by creativepart

Have you tried putting a plastic dish pan in the bathroom sink and then dumping its contents into the toilet?

Ding Ding, Yes... we have now. We got a winner, but no chick'n dinner

My wife found this 7.5 cup ( 60 oz) bowl in the kitchen that she never uses.
It fits inside the bath sink perfectly and gives us room to wash hands, brush teeth etc.

Another thing I like about this is that we only need to use it if we need to use it if that make sense i.e. We will shower and use water like normal and when / if we hit 2/3rds Gray tank, I will pull out our new CreativePart (aka contingency bowl)

Gosh I love this forum, for some of us, it takes a village to own a RV.

[Ray,IN]

Originally Posted by dkoldman

At least WBGO plumbed the Outdoor sink to the black tank, but to nullify that wisdom, they switched to a momentary switch n v2 of our Year model. Using the outdoor sink is a PITA and requires cleaning after each use trying to coordinate the water and the drain pump. If drain pump can stay on while both hands are free our results may change. On our last trip, my wife held the switch while I cleaned items from the grill.

If I were able to divert bath sink to black tank, I would prefer to have it connected with a valve so you could have the flexibility to choose what you need. Our black tank is never close to being full. I know that is a good thing, but if my Gray is full, I have to dump it. While I am set up for dumping, I might as well dump the black even though it may only be 15-20 gals.

But all of the above aside, if we can find a small portable wash basin that fits into the sink, that may be the ticket We could use when washing our hands, brushing our teeth etc. It would have portability so we could flex based on actual tank volume. It is tiny sink as it is, but this is very good idea

I see no reason why you cannot replace the momentary switch with an on/off switch, all either does is break the connection when off

[dkoldman]

Originally Posted by Ray,IN

I see no reason why you cannot replace the momentary switch with an on/off switch, all either does is break the connection when off

Replacing the momentary switch is on this thread https://www.winnieowners.com/forums/...ml#post3943726

I am actually expecting the custom switch tomorrow or Saturday.

The fact that the momentary requires a press and hold as needed is why I wish to change, In addition to having true ON/OFF I want the LED lights so it will require some additional wiring, but based on what I learned on adding a new bath switch, this should be easier task.

[Wyatt]

When we dry camp, washing dishes in the sink with a portable washbasin in the sink, and then pouring down the toilet, evens out the two tank levels. And as a bonus, the black tank was way easier to clean out with all that extra soapy water…

[dkoldman]

Originally Posted by Wyatt

When we dry camp, washing dishes in the sink with a portable washbasin in the sink, and then pouring down the toilet, evens out the two tank levels. And as a bonus, the black tank was way easier to clean out with all that extra soapy water…

9 times out of 10, for what we need to wash, my wife normally washes outside and that sink pumps into the black tank; so we are good there; except for that PITA momentary switch that I am working to replace on another thread.

https://www.winnieowners.com/forums/...ml#post3943726

I hope to get more soap added via the bath sink if we get t 2/3rds full on gray tank. We use 8 oz of the Thetford anyway and it works very well on the black tank. It is in part why I was wanting this Thread's mod because I found myself dumping the black tank 80% of the time when it was only 1//3 full. Getting more gray into the black is my goal. Dumping from bath sink to toilet that is right next to it gives me hope. I can't wait for next trip to see how it works in real life.

[dickb46]

I'm glad I read this thread, I ordered that Twist On Waste Valve instantly ;-}
dickb

[Nalle]

This is my $20 and 2 minute fix. Works great with my tank layout. When Grey Tank approaches full, close added third valve and open Grey. Then open Black and let gravity do it's thing. Then close Black and leave added valve closed until time to dump. Then close Grey and open Black and added valve. Follow with Grey.


https://www.winnieowners.com/forums/...1&d=1696261054