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Black and gray tank question

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TEO

RVF Newbee
Joined
Jul 20, 2025
Messages
2
Location
Goodyear AZ
RV Year
2018
RV Make
Newmar
RV Model
Bay Star 3124
RV Length
31
Chassis
Ford
Engine
Triton V-10
Fulltimer
No
Picking up my new to me 2018 Newmar Bay Star 3124 Saturday.
Never owned a motorhome before and will be doing some short 2 or 3 day trips just to get familiar with everything until I can get some time off later in the year.
My question is should I empty the black and gray tanks after short trips?
If it matters there will probably be 2 or 3 weeks between trips.
 
I would empty them at the end of every trip and flush the black tank. Helps cut down on odours. I'm also not sure if they're designed to be full when traveling.
 
Picking up my new to me 2018 Newmar Bay Star 3124 Saturday.
Never owned a motorhome before and will be doing some short 2 or 3 day trips just to get familiar with everything until I can get some time off later in the year.
My question is should I empty the black and gray tanks after short trips?
If it matters there will probably be 2 or 3 weeks between trips.
One gets a better flush with a full, or near full, tank. If you can add as much water as you can to the black tank before you dump it will help get rid of any sludge even if you have a black water rinse. Dumping a tank with not much in it will allow sludge to build up. If there is a water seal in your toilet and your p traps are full, you shouldn't have to worry about any smells. I would wait until you have something worth dumping.
 
Don’t stress about it. Use a top grade tank additive. I’ve become a believer of West Marine Tank treatment and my combined grey/black tank has contents all the time. It’s an incredible product for a great smell. I’ve used Unique DigestIt enzyme treatment as well with good results.

With. 145 gallon tank, I make sure to get it pretty full before dumping.

I feel seals stay more pliable and valves work better when they stay moist.
 
When you flush the black tank, should you close the valve and let it fill a little? I’m not sure how the flush works, whether it sprays water inside the tank or just fills it.
 
Hey guys…
Please complete your Profile with signature lines so that we all know who you are and WHAT RIG YOU HAVE. Very hard to address questions that may be specific to your make/model/year without knowing.

Here’s the link on how:
 
When you flush the black tank, should you close the valve and let it fill a little? I’m not sure how the flush works, whether it sprays water inside the tank or just fills it.
You haven’t stated which rig you have, but this is what I consider the “BEST” standard practice for any tank, whether a “fill” or “flush” inlet.

1. If your tank is fairly low, I would fill it to at least halfway. This will depend on different “personalities” of tanks, but having that volume behind all the waste will help give it that fast push to get the solids moving better.

2. Near the very end of dumping, I will turn the fill/flush on to let a bit of fresh water run down the tube and help clear the valve. While this is a bonus step, I’ve had plenty of times where solids can find their way into the gate valve’s seal groove and be VERY stubborn to get out after you’ve jammed it home with a push of the gate.

3. Fill your tank up; again, tanks can be different, but if I wanted to be clean as possible, I’d fill back to 100% and give it a complete dump again.

If you KNOW you have a sprinkler head flusher port, then you would use that when the tank is empty. Use the spray to wash the sides down, dumping a couple times in between until you have CLEAR discharge. How far you fill the tank with that sprayer will…once again…depend on the personality of your tank and the amount/consistency of the waste inside.

Whether you leave it DRY or 10% filled with chemical is up to you and your usage. On our coach, I keep it wet since it’s a combo tank and I’m always using our plumbing even in between trips for maintenance, hand washing, etc.

HTH
 

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