Kitchen Sink to Black Tank

RMILES · 07-27-2017, 02:15 PM

Hello all, I am new to the forum and am hoping someone can help me. I bought the 2016 Forest River Sabre 25RL last year and have always thought the black tank was filling up more than it should be, we try to use the toilet as little as possible. We just went to Montana for a week and we ran out of water and my wife said the kitchen sink was smelling bad the last couple times she washed dishes so I checked the monitor and the black tank was full and the grey tank had very little in it. I emailed the factory and the reply I got back was that if I think there is an issue I should take it to a dealer. That is a very poor set up if it is supposed to be plumbed that way and the factory should be able to tell me if that is the way it was plumbed and why! I don't want to pay to have it replumbed or to even have it looked at. The other thing I would like to know is this a health hazard having it connected to the kitchen sink. Any help or advise would be greatly appreciated...

Canadiancrew · 07-27-2017, 02:23 PM

I am not saying it is not plumbed that way but I doubt it. Those sensors tanks sensors are notorious for false readings. Crude bulids up on them. So the black tank may not be full. You will need to watch how much comes out of each tank when you dump. The smell from the sink may be another issue with crude in the traps. I think you may be jumping to conclusions to quickly.

Semperfi24 · 07-27-2017, 02:29 PM

The easy way to verify this, though I admit you really shouldn't have to do this, is to run some water through it. Id suggest doing this at a campground unless you have a dump station at home. Because I assume you have some water in your gray. But either way, unless you have a way to collect it and dispose it (even if right back into the gray, I'd use a sewer connection at a campground). What I would do is connect the sewer hose, open the gray tank, and let anything in there drain out. Then, with the gray tank open, have someone turn on the shower, and watch for it to come out the gray tank and down the sewer hose. Then stop the shower water. Next, have them turn on the kitchen sink, and see if the same thing happens. If the water is going down the drain, but not out the sewer hose, then you know it is going into the black.

I only bring this up because it was a recent thread on the Mini Lites about the bathroom sink draining into the black. Apparently this is something that happens, and some of the mini lite owners confirmed it. So I went through the procedure above to verify if my bathroom sink went to gray or black, and I am thrilled to report it went to gray. I am assuming you have one gray tank, but if you have more than one, you'll just have to account for that in your experiment of turning on water with the gray tank open.

As far as health hazard, that is an interesting question. It didn't cross my mind with regard to bathroom sink into the black tank thread, but it definitely makes you think about it differently in the kitchen with food prep, dishes, etc.

RMILES · 07-27-2017, 03:31 PM

Thanks Canadian Crew and Semperfi for your quick responces. I have a dump station not to far from my house so I will try that with the shower to see where it is draining and then the kitchen sink. On my way home from Montana I did dump it and with the grey water I hooked a short section of garden hose up to my drain cap and dumped it that way and only a gallon or two came out of my gray which would have been from my bathroom sink (bathroom and shower are upstairs so if the black tank overfills and it is hooked to my kitchen sink it will overflow through my kitchen sink before it goes up through my toilet) when I dumped the black through my regular dump hose that is where all the fluid was. If that is the design and I want to replumb I guess I'm stuck paying for it? Again, thanks for your input - much appreciated!

TitanMike · 07-27-2017, 04:06 PM

Quote:

Originally Posted by Semperfi24

As far as health hazard, that is an interesting question. It didn't cross my mind with regard to bathroom sink into the black tank thread, but it definitely makes you think about it differently in the kitchen with food prep, dishes, etc.

Do you consider it a health hazard in your home kitchen sink? That drain is connected to the same pipes as all the toilets in your house.

If there is water in the P-Trap under the sink no "fumes" should be coming up from the sink unless the water in the P-Trap itself is "foul".

It also pays to make sure the roof vents are clear and not plugged with a wasp nest or such.

Even with a good holding tank chemical (in both tanks) smells have a way of infiltrating a travel trailer/motor home. It often just depends on how the wind blows.

BTW, I keep waiting for someone to invent a holding tank gauge system that doesn't rely on just screws through the side of the tank as sensors. One piece of wet toilet paper can keep an empty tank reading "full" until it gets washed off one way or another. My old trailer black tank "sensor" consisted of just flushing and looking down into the tank.

RMILES · 07-27-2017, 07:30 PM

Thanks Mike, I never thought about it in my house but I think my toilet in my house would overflow before my sink. The biggest issue I have is that we use the the kitchen sink more than we use the toilet when we camp and we dry camp so when the black tank is full now we will have to wash dishes outside in a tub. We really like the trailer so I will have to decide wether to replumb or not. Technically it should not overflow because the black tank is 42 gal and the fresh tank is only 31 but we carry extra water with us which if used through the kitchen sink will put us in that bad position. Thanks for your reply, much appreciated. BTW I agree with your dog, I take an afternoon nap as often as possible!

Ron

rbrand · 07-28-2017, 01:03 PM

My kitchen & Vanity sink dump into the Grey tank. With careful inspection I'm positive my shower goes through a P trap into the black.

TitanMike · 07-28-2017, 01:45 PM

Quote:

Originally Posted by RMILES

We really like the trailer so I will have to decide wether to replumb or not. Technically it should not overflow because the black tank is 42 gal and the fresh tank is only 31 but we carry extra water with us which if used through the kitchen sink will put us in that bad position.

You might send an inquiry off to the manufacturer to see if that setup was what they intended. If not, and someone just took the shortest rout from point A to point B in the factory they "might" correct the problem for you.

If they intended it to be that way then it's possible that there is an issue with routing the drain pipe to he holding tank due to a structural obstruction.

If it was mine I'd be inclined to re-plumb. If you can access a clear route from where the sink line passes close to the grey water tank I'd cut out a piece of the pipe, glue a cap on the part going to the black water tank, then finish plumbing to the gray water tank. Depending on the tank there may be alternate connection points where a discharge pipe can be "glued" in and hopefully one of them is in a suitable place. There are flexible 2" drain pipe "solutions" that often allow one to perform some difficult connections.

TitanMike · 07-28-2017, 01:48 PM

Quote:

Originally Posted by rbrand

My kitchen & Vanity sink dump into the Grey tank. With careful inspection I'm positive my shower goes through a P trap into the black.

Not an ideal situation. In that case what goes down really can come back up ---- in the wrong place.

RogerD · 07-29-2017, 07:06 AM

The kitchen sink on our toy hauler came from the factory with its drain dumping into the same tank as the garage toilet. They called it a kitchen gray water tank on the literature. I added an independent black water tank for the toilet but it was a lot of work and many trailers don't have the space for additions. As others have mentioned, it isn't a health issue as long as water is in the P-traps. When our kitchen and toilet drains were connected, sometimes dumping the system would siphon the water from the P-trap. Also I found the system had a mechanical vent under the counter rather than an external vent and if this malfunctions it can allow sewer gas in your cabin. Good luck.

RMILES · 07-29-2017, 04:53 PM

Thanks Mike & Roger, I'll pull the belly pan and check if I can reroute the plumbing with your suggestions. Very much appreciated!

TitanMike · 07-29-2017, 05:31 PM

Quote:

Originally Posted by RMILES

Thanks Mike & Roger, I'll pull the belly pan and check if I can reroute the plumbing with your suggestions. Very much appreciated!

Just something to think of should you not find easy access tot the tank itself, if there is a length of 2" pipe between tank and valve you could tap into it there with a "Y" connector. When at full hookup site and you have the gray water valve open the sink water will just dump without running through the tank. When the valve is closed the sink water will just back up into the tank, just filling it from the bottom. As long as the tank is vented it will fill and empty like normal.

thaithco · 07-29-2017, 06:36 PM

Don't understand why there's 2 tanks to begin with. Half the time I'm rebalancing Grey to black anyway then dump both to same location. It's not like I'm repurposing my Grey water. If you have reasonable traps under each drain there's no smells. So I always look at it like I've got 60 gallons of nasty water and not I've got 30 gallons of Grey and 10 of black so I've gotta dump the Grey.

You may also like: