Grey water tank flows into Black water tank?

[dgmelp]

We are new to RV'n and recently bought an old 1990 Holiday Rambler Aluma lite XL. We spent the last two months renovating the unit and now we're ready to take it out on our first trip.

However, when we were disinfecting the fresh water tank, and draining it, we noticed that when the Grey water tank was full, it must have started overflowing into the Black water tank. We had to drain both tanks when we were done..and when the Grey water holding tank was full, the Black water holding tank was also almost full, though we had not used the toilet at all since we flushed the system after buying the unit.

We know the Black water tank was empty - we recently flushed both tanks. So, the water could have only come from the grey water tank...is that possible, or even normal?

Is this okay, and should we leave it alone, or is it a problem we need to address?

Thanks!
David Marcus

[tmh462]

Welcome to the forum. Some trailers will have the bathroom sink drain into the black tank. This is done for ease of plumbing as well as giving a bit more liquid in there to help move the solids along.
Have you noticed this overflowing when you are using the bathroom sink, or when you put water from any sink into the system?

[WeBeGone2]

I had a HR Alumilite that was a 1994 model. The bath sink did go into the black tank. I also think that the shower went in also. My black tank filled faster than the grey all of the time.

[CD]

Originally Posted by dgmelp

We are new to RV'n and recently bought an old 1990 Holiday Rambler Aluma lite XL. We spent the last two months renovating the unit and now we're ready to take it out on our first trip.

However, when we were disinfecting the fresh water tank, and draining it, we noticed that when the Grey water tank was full, it must have started overflowing into the Black water tank. We had to drain both tanks when we were done..and when the Grey water holding tank was full, the Black water holding tank was also almost full, though we had not used the toilet at all since we flushed the system after buying the unit.

We know the Black water tank was empty - we recently flushed both tanks. So, the water could have only come from the grey water tank...is that possible, or even normal?

Is this okay, and should we leave it alone, or is it a problem we need to address?

Thanks!
David Marcus

Check all of your plumbing and valves and try to understand how they work. Our TT has 2 grey tanks with a valve at each tank and a valve for the grey and black at the main drain. I have the grey valves open so they equalize. It is possible (on our TT) to have all valves open and the end cap on and have water run from tank to tank.

[Pusherman]

Assuming there is no problem with your plumbing system, this may actually be desirable.

It is always good to have lots of water in your black tank to flush away the solids. In my coach I have more black tank capacity than I do gray tank. I would like to figure out how to get some of the gray water into the black tank for all of the above reasons.

[Dsouthw524]

The setup is designed that way as stated to get more liquid to the black water tank to avoid "build up" problems as many users do not use enough water to flush and have blockage problems.

this solved a problem that was prevalent in older MHs and trailers.

[dgmelp]

Originally Posted by DSouthw524

The setup is designed that way as stated to get more liquid to the black water tank to avoid "build up" problems as many users do not use enough water to flush and have blockage problems.

this solved a problem that was prevalent in older MHs and trailers.

So, your saying that the system is setup to flow from Grey water to Black water when the Grey tank is full? Some of the other answers have the bath sink and shower flowing directly into the Black tank, but that would only leave the kitchen sink flowing into the Grey tank.....

I should have mentioned above that our Aluma Lite XL is a Class A MH..not a trailer, in case that would have changed any answers?

Thank you!

[lostagain]

Sounds like someone put a hose between the black and gray tanks probably with a check valve so the black tank can't flow into the gray tank. I have thought about doing this but never got around to it. This will give you more gray tank storage.

[rebelone]

The previous Winnebago RV I had, the kitchen sink went into the black tank. This was plumbed from the factory. I would use a dish pan in the kitchen sink to help control the over filling the black tank.Dump it in the shower drain. To keep a closer watch on my tanks I installed the see level gauges. Most motor homes do not use this system. It works great as long as you watch your kitchen sink water use. Hope this helps.
Rebel

[Easyrider]

Pusherman, buy one of those add on valves to your dump hose hook up and just close that one and open the factory grey and black water valves and you will equalize both tanks and be able to fill both to capacity before having to dump.

[ga traveler]

I have never seen a shower plummed to the black water tank, but i have seen several bathroom sinks plummed to the black tank. Airstrem did it on my 1985 345
MH. I talked to the factory and they said it was to help flush the black tank. They got so much negative feedback they did away with it.

[ksg5000]

Gray water tank always fills up before the black water tank so your "problem" would not be considered a problem by some. Depending on the rig you might have one of your sinks plumbed to the black water tank - it's also possible the prior owner did some modifications so that you have a one way valve dumping into the black water tank when the gray water tank hits a limit. You may have to crawl under the rig and examine the plumbing.

[JimM68]

Your tanks should not actually be plumbed together, they have rules against that.
As everyone said tho, it's not uncommon to have some other fixtures connected to the black tank.

Hook her up to water, and run each faucet in turn until you figure out where it is going?