GRAY and WASTE HOLDING TANKS??

You don't fill the waste and gray tanks. As you use the fresh water, the water will go to the appropriate tank, waste or gray. You start with a full fresh tank, and empty waste (black) and gray tanks.

You got your answer while I was still typing. Slow fingers....

never mind. Just found the answer. thanks everyone

thanks. Gotchya. I can't find how many gallons my fresh water tank can hold (the capacity). Do you just fill until it starts coming out the top?

OK, there are 3 tanks on most RV's. Some have 4 since they have 2 separate gray tanks, but I will stick with the norm here.

1. Fresh water tank - this is the tank you fill to carry water with you for showers, drinking, flushing the toilet, etc.

2. Gray tank - this is the tank that the shower and one or both sinks empty into. It is considered less dirty than the black tank, and is dumped after the black tank is dumped to rinse out the stinky slinky (aka sewer hose).

3. Black tank - this is the tank that the toilet and maybe the bathroom sink empty into. It is dumped first so the gray tank water can flush it out of the line.

Sooooo, you only have 1 tank to manually fill, the fresh water tank. The other tanks are filled by your using water in the MH, and must be dumped when full.

One note, always be sure the waste tanks are 2/3 full or more before dumping to facilitate good flushing action to get all of the solids out.

You probably have three tanks. Fresh water tank, black tank, and gray water tank. You fill the fresh water tank from the outside, that is the water that comes out the faucets. Toilet goes to black tank. Rest of the drains go into the gray tank.

mike73 wrote:
ok but does that mean there is 2 different places to fill the tanks?

Um, you fill the FRESH water tank from outside.

ok but does that mean there is 2 different places to fill the tanks? I only see one fill location. Back left side of RV.

It's two separate waste pumping systems. All of the waste water from sinks, bathtub/shower goes to the grey tank and only the water from the toilet goes to the black tank.

mike73 wrote:
wondering how filling from one source is filling both tanks.

Separate piping.

Usually no.
Black water will be completely separate from gray.

You should have two separate pull dump valves on the RV.