Black/Gray Water With Full Hookups?

[OldCarBum]

We purchased a new 2022 Flagstaff 22TBS travel trailer.
We have taken it out twice.
Our first trip out we had city electric and water hook ups but no sewer hook up.
Our second trip we had full hook ups.
I’ve read a couple of articles and found there was a contradiction about how to hook up and use the sewer connection with full hook up.
One article said to connect the black/gray hose to the trailer, then lconnect it directly to the sewer, open the two valves and let everything flow.
The other article said to make the connection from the trailer to the sewer, but leave the valves closed and only open them when the tanks are full.
Does it matter?
Is one way better than the other?
To me it makes more sense to open the valves and let it flow, but we are new to RV life, so that’s why I’m asking.
Should we use the tank sanitizer with full hook ups if we let everything flow?

[TacomaJoe]

I'm in the keep the valves closed camp. There isn't as much water flushing in the RV toilet. At home my toilet dumps 3+ gallons of water to move the waste along (not so in the RV). At home my ABS lines are smooth and have a 1/4" per foot drop all the way to the main line in the alley. My RV hose is bumpy and not at a perfect grade.

I wait for nearly full tanks. Pull the black and drain it, then pull the grey and let it clear the lines.

[Iwritecode]

Leave them closed.

[chriscowles]

Leave the black closed so you don't build a poop pyramid under the toilet. Leave the gray closed so you have something to rinse the sewer hose with after you dump the black tank before you leave.

I'm at a full hookup state park. We've been here two nights and leave Monday. I'll dump the gray tomorrow AM so I don't overflow, then close it again.

That leaves me a full day to accumulate something to rinse the hose after the black tank. I do have a black tank rinse connection but that's unnecessary effort at this point.

[Reverse_snowbird]

The reason we keep both valves closed until dump time is the possibility of sewer gasses entering the rig when the valves are open.

[5picker]

Leave closed until full.
If you leave the black valve open, liquids will flow away and leave the solids in the black tank and create a blockage. (often called poop pyramid) It can become like concrete!

R/V waste drains are not like home drain systems. Not nearly the same water flow. You need the accumulation of water in the tank to carry things away. Water (and lots of it) is your friend when it comes to R/V waste tank draining.

[kenandterry]

Originally Posted by 5picker

Leave closed until full.
If you leave the black valve open, liquids will flow away and leave the solids in the black tank and create a blockage. (often called poop pyramid) It can become like concrete!

R/V waste drains are not like home drain systems. Not nearly the same water flow. You need the accumulation of water in the tank to carry things away. Water (and lots of it) is your friend when it comes to R/V waste tank draining.

X2
Leaving valves open is the “lazy man’s way” but you’ll end up with way more problems.

[loyda]

Keep black tank closed. Water is the key . Always add a few gallons of water to your black tank after empty and flushed out.

[kfd82]

We leave the gray open and the black closed. About a day before we leave I'll close the gray so it can build up some water.

Before we leave I'll dump the black, then dump the gray.

[NavyLCDR]

RV holding tanks are called holding tanks for a reason. They are not designed to be flow through sewer systems.

[emm-dee]

I don’t even hook up the system drain hose until it’s time to leave or five days…which ever comes first.

[Oaklevel]

I do the same as all above. Keep the black tank closed. Use the grey tank for rinsing the waste hose.

I always wonder about those that come in in the middle of the night, set up and insist on hooking up their waste hose. I too often do it a few days later.

[rowdy boys 3]

Closed until you're ready to dump, if not ready to depart the campground, close um after you dump..

[Boomerweps]

GREAT advice in all the above posts. Solids need water to keep moist and flow.
Make sure you are able to reach your site sewer hole, but don’t bother connecting it until you decide to dump. Many recommend not leaving the stinky slinky attached when not dumping. Less things to trip over or worse get pulled out or apart. Almost a SHTF situation

And one less thing to do setting up your campsite.

[OldCarBum]

Thirteen out of thirteen responses say to keep the valves closed, let the tanks fill, then flush them out.
That’s what makes this forum so great.
I’m still learning and appreciate all your feedback.
Thanks again!

[OldCarBum]

Originally Posted by Boomerweps

GREAT advice in all the above posts.
Make sure you are able to reach your site sewer hole, but don’t bother connecting it until you decide to dump. Many recommend not leaving the stinky slinky attached when not dumping.

Thanks, I learned that the hard way.
I got everything leveled and set up and found I was about two inches short.
I was worried about that slinky every time our pups run through where it was at.
Thanks,

[SailorSam20500]

Originally Posted by kfd82

We leave the gray open and the black closed. About a day before we leave I'll close the gray so it can build up some water.

Before we leave I'll dump the black, then dump the gray.

If we are staying more than 2 days, I follow the above and I hook up the waste hoses on setup, otherwise I would have to crawl under slides to get the work done and open the valves. Black tank is closed until full or we are departing - black tank valve is accessible without getting under a slide. One difference from many, for FHU sites, I use a Valtera Sewer Solution setup, so my dump hoses are 3/4" garden style hoses. And the SS allows a clean water flush of the hoses once the tanks are empty.

[kfd82]

Originally Posted by Oaklevel

I do the same as all above. Keep the black tank closed. Use the grey tank for rinsing the waste hose.

I always wonder about those that come in in the middle of the night, set up and insist on hooking up their waste hose. I too often do it a few days later.

Thats me. No matter when I get in I do the full hook up/set up. I do the same thing everytime so I dont forget stuff, also so I'm done with it. I dont want to have to fidget with getting under my slide to hook up a hose and dump my gray on day 3.



But your point is valid! If my sewer connection wasnt under a slide I might wait until I actually need it.

[DouglasReid]

Originally Posted by OldCarBum

Thanks, I learned that the hard way.
I got everything leveled and set up and found I was about two inches short.
I was worried about that slinky every time our pups run through where it was at.
Thanks,

Get a extra hose for an extension. Will save you moving when time to dump next time.

[OldCarBum]

Originally Posted by DouglasReid

Get a extra hose for an extension. Will save you moving when time to dump next time.

I already did.