Rv tech here. When confronted with this I usually tap on tank underneath if possible. If it sounds like it is hollow or not full then blockage is more likely closer to toilet bowl with possibly the dreaded poop pyramid as mentioned by others. Get the yard stick(or similar) and shove down as far as you can ans swivel it around to free up blockage. If tank sound full when tapping blockage is usually on first few elbows of black pipe as it leaves tank. I’ve had previously unseen second waste gates discovered close to tank exit and partially closer for years until problem occurs. If you have garden hose with water pressure you can fish it up from outside valve location. But stand back when it lets loose!
Are you somewhere with hookups and are you leaving your sewer hooked up with the valve open all the time? If so, you may have the dreaded poop pyramid and it’s completely clogging everything up.
When you’re hooked up you need to leave your valve closed until the black tank is full and then flush it all at once. When you leave the valve open all the time, just the liquids flow out but solids stay, creating a poop pyramid. I’ve heard it’s really bad and hard to get rid of. ????
Assuming its below freezing outside and the exposed piping and valves are frozen you will need a way to unthaw them. If thats not possible carefully remove toilet bowl and call a septic company to come remedy your situation. It wont be cheap. After this experience there shouldn’t be a “next” time, but if there is- stop using the toilet when you see it isnt draining.
Also your sewer hose may be frozen if its been left connected. Good luck.
My toilet drops directly into the black tank and the black tank is only stopped from making a mess by the valve. Any time I have a issue, I can look down into the tank with a flashlight.
I’m guessing you have a paper blockage between the valve and the tank. Maybe a plumber would have the right tools or buy a snake from a hardware store. Maybe a camera scope tool would be useful?
UPDATE
It was a blockage.
Got a better snake line and was able to push it through after 30 minutes. ????
But pipes are frozen so I can’t properly flush it out until things warm up in a couple of days.
Thank you to everyone who commented. Stay safe out there and keep plumbing tools handy.
I would get one of the things you hook up to the outside of the tank and flush it backwards.
Where’s your maccerator???Clearly black tank is full and you are trying to flush into a full tank.
You don’t need a plumber, you need some long gloves, a peg for your nose and a long stick.Shove a hose pipe up the drain pipe and flush out the drain while agitating with the stick….
Oh and stand well back 😀
