sewer connections

Our black tank fills in 3-4 days and our grey tank can fill in less than 24 hours. I leave the grey open because if I forget and my wife is standing in water during her shower, I hear about it lol. I run water in sinks and shower to be sure water is in the trap and I let part of the sewer hose dip so there is water there as well so no sewer gases. I will close the grey tank before the last showers. I have a black tank flush but generally only use it a couple times a year. I dump the black tank and then usually step on the peddle for a bit to run water through it, this has work on various trailers for 15 years.

Unless you have a washer/dryer, then you need to figure out which grey tank that dumps into and leave that one open.

Personally I always leave the black closed, the galley grey closed, and the bath grey open.

I also use a Flush King so I'm not worried about having 'clean' water to use after dumping the black.

baldyman1974 wrote:
When I hookup to park sewer do I open any of the valves?

Some folks open the gray but my answer is NO, do not.

now.. Some specifics and modifications

Where I am now I'm using a SLUNKY (Tm) sewer hose support so the hose is a near straight line from the elbow under the rig to the elbow into the ground.. No dips, If I leave a valve open sewer gasses will back up the hose and .. Well have you seen those adds for chemicals (Which by the way are a waste of money) showing the stinky RV? Yup, that's what happened.

Closed the gray vale (The one I'd left open) and stink quickly vanished.

The alternative (and this is how Gray #2 is plumbed) is to have a hos that forms a natural "Trap" (Gray 2 (Wash water, no kitchen sink) on my rig drains ia a 3/4 inch GRAY garden hose wich is lying on the ground.. Since both the inlet (RV end) and outlet (Sewer end) are more than an inch above ground (I drilled out th hose fitting on the sewer end elbow) a water trap is formed blocking the stink.

This can be done with a 3" hose too but it takes a much larger "DIP" My neighbor did it that way.

I would leave BOTH closed until near full. Then dump before leaving or sooner if necessary.

The more contents and water in the black tank the more efficiently it will empty. The grey tank will flush the valve and hose when dumped.

The surest way to end up with the dreaded poo pile is to keep the valves open.

I leave the grey open and the black closed. Moving day, I close the grey just before our showers. I then empty the black and flush with the shower water. After three flushes, I allow some shower water to fill the black then close it. I then finish draining the grey tank and I'm ready to travel. My opinion is as you shower, do dishes etc. that water is hot to warm and anything from the shower and/or kitchen sink is still suspended in that water. By allowing it to drain immediately, you're moving those suspended particles into the sewer with the hot water. Same with soap scum. That's hot water being sent thru the sewer hose. By allowing water to sit in your grey tank for days, those suspended particles settle to the bottom of your tank where they mix with any food particles, grease or whatever from your kitchen sink. The water cools and all that mess now gels. When it's time to empty the tank, any clear water must pass over and/or thru that gooey mess before emptying into the sewer. Also, you're now sending cold water thru your hose. Hot water will keep things a lot cleaner than cold water.....Dennis

What even you do..........LEAVE BLACK CLOSED UNTIL DUMPING.
Liquids will drain out and leave piles of poop behind if you leave it open

Grey tank.......personal preferences come into play.
Some leave open and then close night before departure
Some leave open
Some leave closed until time to dump


My preference......I leave it closed otherwise liquids will drain out leaving 'stuff' behind to accumulate (soap scum, body oils, hair, food particles, grease etc.)
I like a FULL tank to carry the stuff out.....weight & volume
Strong river carries boulders-----gentle creek barely moves pebbles :B

Moved from Forum Technical Support

The two of can easily go a week before having to dump the Black tank.
I open the Grey on arrival. Close the day before I dump the Black. After dumping the Back, I then open the grey to flush the slinky.

I open both grey tank valves when I hookup, and leave them open until ready to depart. That way I don't have to monitor them (or dump them) no matter how many showers we take.

I understand the reasoning behind keeping enough in the grey tank(s) to flush out your "stinky slinky"; however, I believe that my hose gets adequately flushed when I use the black tank flush port to flush the black tank after I empty it.

I make sure the black tank is at least 2/3 full. If not, I add water to it. Then I empty the black tank, then close the valve and turn on the hose to the flush port long enough to fill the black tank about 1/3 full. Then I dump the black tank a second time. I finish up by flushing the black tank for an additional 5 minutes, making sure the outflow runs clear before I shutoff the flush hose. I'm sure this puts plenty of clean water thru my "stinky slinky".

Works for me!