dumb question about sewer hookup 2017 320 S

melpeter

There are two drains, one for gray water and one for black water. If I'm in a park for a month with full sewer hookup and the black tank is hooked up to the sewer, what happens to the gray water? Do I have to intermittently go out and disconnect the black tank and connect the gray tank? Is there a Y fitting I can buy that will connect the two drains into one line? I'd like the black water and gray water to go down the tubes together. 

RollingBnB

That’s what I did. Got a Y fitting, a 45 elbow and a 1 ft sewer hose. Put it all together and we can dump black, then gray without moving anything. Got the parts at CW

Sharon_is_SAM

@melpeter, you may want to be careful about leaving the valves open on your sewer lines.  Everything I have read indicates that you risk build up of drying paper etc. on the sides of the tank.  Recommended to fill the tanks about 3/4 full before you empty and use Calgon down the tank to keep things moving.  Also, sewer gases may be a concern.

melpeter

Definitely I have a lot to learn. I thought all those RVs I’ve seen with full hookups just left their valves open, carefree! Just like the sewage system at home. Flush and forget it. Thanks. 

RollingBnB

Definitely do not leave the valves open. Not only sewer gas but you run the risk of critters crawling up into the holding tank, and getting the dreaded poop pyramid.

Michigan_Mike

It's a good question and this is how we learn.  I modified the seperate valve pipes and combined them into one on my former 320 T@B to allow one hook-up and less work.  Search the site and you will find these mods, however I would recommend that this project be taken on only after careful research and consideration as there isnt a lot of room for error cutting the piping and retrofitting the new valve configuration.  

As noted, when in a park you keep the black valve closed and only dump when the tank is nearing full as this helps move material and you dont want waste or paper drying inside the holding tank.  Gray water is different but also helps clean the hose after the black tank is emptied.  

Here is a helpful FAQ on homding tanks.

https://www.coltonrv.com/rv-gray-water-black-water-faqs/

melpeter

Thank you!

melpeter

I read the Colton RV FAQs. Very helpful! But now I have another question. They say “After you dump both tanks, thoroughly flush out the tanks...” How do you flush out the tanks? 

Sharon_is_SAM

@melpeter, for the gray tank, you can simply close the valve and fill the tank via the faucets or shower, then drain.  You have other options with the black tank:

1.  You can fill the tank by flushing, using your shower wand, or buckets of water and then drain.  Some folks may suggest driving around with an almost full tank to loosen things up a bit, then drain.

2.  Use a device for back-flushing your tank.  Search “Tank flush” here on tge forum fir various discussions.

3.  Camco has a wand that you can hook up to a hose or maybe even screw it onto the end of your shower hose.  You stick the wand end down the toilet (flush valve must be held open) and rinse away.  As our tanks are very shallow, I am not certain of the effectiveness of this approach.  

Because of the sleeping area proximity to the bathroom, you really want to keep your tanks clean and your valves closed.  Make good use of tank additives (Happy Camper for odor and Calgon to prevent sticking debris).  Be careful what you put down your gray tank to prevent odors - we use tubs to do dishes and discard the gray water in gray water dumps where available).  Paper plates help, too.  Also, keep your P-traps from drying out.  Water in your shower trap will prevent tank odors from wafting up into the TaB.  

dsfdogs

@melpeter I've seen where people that stay in one place for a while leave the gray valve open (obviously hook up your sewer hose to that valve). Then when you know you'll need to empty the black tank in a day or so, close the gray valve and let the tank fill. Empty your black tank, flush it out the tank if you want, then switch the hose to the gray tank and empty that. The gray water helps to clean the sewer hose. As mentioned, if you leave the black tank open all the time, then the water will drain but leave behind the "solids".