Newbie Sewer Questions

[StevL]

I have asked several different RVers and I get completely different answers.

When you have full sewer hook up do you:
Leave the black tank valve open?
Leave both black and grey open?
Keep black closed and drain as needed?
Keep black and grey closed and drain as needed?

Seems simple....

Thx,
Steve

[Bobb.25]

The quick answer is to ONLY open the black tank valve to empty the contents of the tank. After emptying the tank you close the black tank valve and dump several toilets full ( 5 gal. ? ) of fresh water into the black tank and add your chemicals. I use "Happy Camper." The gray tank valve can stay open until a day or two before you plan to decamp, then close the grey tank valve, let the tank fill up with shower and sink water, then dump the gray tank last to rinse out your stinky slinky.
Bob

[wildtoad]

This comes up all the time and you'll get various answers. I would say that most will tell you to leave the black tank closed until you need to empty it, and never leave it open. Leaving it open will create a lot of problems for you or future owner.

Regards to grey, I tend to leave closed until I need to empty for the same reasons as black although the consequences are less. Folks with dish washers, clothes washers may have a larger need to leave it open.

[Mr. Dave]

Here's my opinion.

With full hookups, keep your black tank valve closed. Monitor the level and dump when needed or just before you leave the campground. That way you'll have lots of room when on the road.

The reason not to leave the black tank open with full hookups is you can have the pyramid effect happen in the tank. This is where the solids can build up in a pyramid fashion and stay there. This happens because the liquid drains away before the solids can go along for the ride.

With your black tank containing both liquid and solids, it'll all goes down the drain when you open the valve to dump it.

On the gray tank, I generally will leave that valve open as you use much more gray water than black so let it go. The night before leaving the camp ground I will close off the gray tank to collect water. That water is used to flush out your sewer line after you dump and rinse your black tank.

Hope this makes sense and helps you decide how to do your valves.

Here's a link to the RV Geeks about water and sewer videos they've produced over the years. They have some really good info.

[mel s]

Originally Posted by StevL

I have asked several different RVers and I get completely different answers.

When you have full sewer hook up do you:
Leave the black tank valve open?
Leave both black and grey open?
Keep black closed and drain as needed?
Keep black and grey closed and drain as needed?
Seems simple....
Thx,
Steve

StevL
When I have a sewer hookup I keep both the black and grey dump valves closed and dump the tanks either:
1.) When they are between 1/2 full and full.
2.) Before hitting the road.
Mel
'96 Safari

[focker]

Keeping your black tank valve open will generally create something like this...

[Pepper2]

Originally Posted by mel s

StevL
When I have a sewer hookup I keep both the black and grey dump valves closed and dump the tanks either:
1.) When they are between 1/2 full and full.
2.) Before hitting the road.
Mel
'96 Safari

I agree with Mel. I would add that if you have a full HU site this is an ideal time to really rinse out/flush your black tank.

[trimacon]

Originally Posted by Bobb.25

The quick answer is to ONLY open the black tank valve to empty the contents of the tank. After emptying the tank you close the black tank valve and dump several toilets full ( 5 gal. ? ) of fresh water into the black tank and add your chemicals. I use "Happy Camper." The gray tank valve can stay open until a day or two before you plan to decamp, then close the grey tank valve, let the tank fill up with shower and sink water, then dump the gray tank last to rinse out your stinky slinky.
Bob

Nicely explained. Agree w/this process.

[530ktm]

Originally Posted by mel s

StevL
When I have a sewer hookup I keep both the black and grey dump valves closed and dump the tanks either:
1.) When they are between 1/2 full and full.
2.) Before hitting the road.
Mel
'96 Safari

I do it this way too. Also this does not let the stink from the sewer come up into your line along with who knows what else may be in there.

[Jimm59]

KEEP BOTH valves CLOSED, until 1/2 or so full/ more/less on Black tank in warm weather, Use LOTS of water in Black tank, pull those levers and whoosh away: as needed., then close, treat black tank with chem, n start over. I like to pull Grey lever, once every couple days: or more if hitting showers/washer harder.
****Reason for keeping grey tank closed, too is to keep methane (sewer) gases from back-washing into RV....

[jrusselltx]

I pretty much agree with keeping the black valve closed and the grey open until close to departure to use it to flush both the black tank (open the grey valve briefly once the black is drained without closing the black valve). I suggest putting a clear fitting on the drain so you can actually see what is going on. Not the most pleasant sight, but is helpful to know when the black tank is really getting clean. I followed an RV Geeks video on flushing their black tank and recovered full use of the sensors after several complete flushes. They have some really good advice.

[TonyDi]

Originally Posted by Bobb.25

The quick answer is to ONLY open the black tank valve to empty the contents of the tank. After emptying the tank you close the black tank valve and dump several toilets full ( 5 gal. ? ) of fresh water into the black tank and add your chemicals. I use "Happy Camper." The gray tank valve can stay open until a day or two before you plan to decamp, then close the grey tank valve, let the tank fill up with shower and sink water, then dump the gray tank last to rinse out your stinky slinky.
Bob

Best way to do it. Closing the grey tank, especially if you use a washing machine, is an invitation to have an overflow. Your sinks P traps will keep sewer odors out. This is the way I've been doing it for years. Happy Camper is excellent additive.

[MSHappyCampers]

When arriving at CG, leave black tank valve closed and grey tank valve open.,

Watch the black tank level and when it is about 3/4 full, OR if you're getting ready to leave the next day, close the grey tank valve to accumulate some water.

Before departing next day, dump the black tank, flush it out good with a hose flusher or by refilling it part way and dumping several times until the water is clear. You should have a clear fitting for your sewer outlet!

Close the black tank valve, add a couple of gallons of water in the tank, and put in tank treatment chemical. We use Happy Camper!

Dump the grey tank, cleaning the sewer hose in the process! Close the grey tank valve.

Job finished!

[dennis45]

Originally Posted by 530ktm

I do it this way too. Also this does not let the stink from the sewer come up into your line along with who knows what else may be in there.

I agree, both closed until at least 3/4 full. In addition to sewer smell with the grey tank open, there can be sewer flies also.
other option for the grey tank is to create a trap in the hose which will prevent anything from the sewer coming back to the tank.