How do you empty septic holding tank?

[Macymac]

Hello,

Just got a 1975 airstream,

I not sure how to empty septic, should i pull main holding tank line out or push it in? If it still dosn't empty, as it is backed up water in shower, your advise would be appreciated very much,


Thank you,

the rookie

[easyride]

On a 75 you have 2 valves 1 for gray water,1 for black water,they are both located in the trunk ,black handle is in the left side of tank,pull up to drain,I always drain black first,then move over to right valve,pull it up,that should wash the black out.After draining push both valves back down. Dave

[moosetags]

First off, welcome to the Forums. We're glad to have you with us.

The valve maker 'main' should be the black tank, and the other valve, usually marked 'auxiliary' is the gray. The black tank holds water and waste from the toilet. The gray tank holds waste water from the sinks and shower. The water backed up in your shower is from the gray tank.

You must attach a sewer drain hose to you dump outlet prior to pulling either of those valves. The other end of the drain hose to a proper sewer dump.

Whatever you do, don't pull either of those valves until you are properly hooked-up.

Brian

[DaveFL]

If you haven't done it before make sure you have the end into the sewer secured, rock, foot or even sewer pipe cover, hard to believe how much the pipe moves when it gets full force black water moving through it.

[Macymac]

Originally Posted by moosetags

First off, welcome to the Forums. We're glad to have you with us.

The valve maker 'main' should be the black tank, and the other valve, usually marked 'auxiliary' is the gray. The black tank holds water and waste from the toilet. The gray tank holds waste water from the sinks and shower. The water backed up in your shower is from the gray tank.

You must attach a sewer drain hose to you dump outlet prior to pulling either of those valves. The other end of the drain hose to a proper sewer dump.

Whatever you do, don't pull either of those valves until you are properly hooked-up.

Brian

Thankyou Dave and Brian - i have it hooked up but have not pulled the left grey aux handle yet - should be good to go now! Take Good Care

[Open Sky]

Any one know what the pipe size of the dump outlet is?