Lavatory Drains to Black Tank?

[B&J]

I have a 2005 28' CCD International and I just recently discovered the lavatory sink drains into the black tank. Shouldn't it drain into the grey tank? I now know why the black tank is filling up so fast. Has anyone else experienced this with their Airstream? I might call Airstream to inquire about this.

[MrUKToad]

That's right, it's the way it's supposed to work; we look upon it as a positive thing in our 2011 28' International. It's often good to add liquid to the black tank to stop any solids from drying out inside the tank when the weather is hot and this is an ideal way to do it. Not had any trouble with overfilling the black tank, either; we often pour the dish washing water down the toilet to balance out grey and black tank loads as well as keeping the solids in check.

[wanderwasi]

This same question came up at the Tech Talks during Alumapalooza 5 a few weeks ago.

Per the AS folks giving the Tech Talk, it's common practice when the bathroom is on one side and shower and galley sink on the other side because getting the drain pipe across the hallway would be a problem.

We found out the hard way with our 2012 Serenity 30' as we emptied the bleach water from our first freshwater tank flush...when it backs up into the sink of the bathroom you can expect the toilet flange to leak too because it's not made to hold back the pressure, only to funnel the toilet waste to the black tank. Thankfully the black tank contents weren't truly "black" but it was still a mess to clean up.

Now that we know this, we love it because it balances out our black and grey tank filling up.

I wish we'd known this before we had to clean up a mess so I thought posting an updated reply to an old post might help someone else just getting started with their AS.

Jase

[Minno]

We actually changed our plumbing this spring before we buttoned up the bathroom remodel by rerouting the bathroom sink into the black tank. We were having problems with too little fluid in the black tank, and this has solved the problem now.

Kay