Mysterious plumbing issue has everyone baffled, and me going broke

[jpass]

So its a small building with 3 apartments, which I rent out. Upstairs is whole floor, and two little efficiency apartments downstairs. The income from it is not large, and sadly right now with the Pandemic, its all the income I have.

Once upon a time, there was a bush planted out front. That bush had grown into the main sewer line, and regularly blocked up the line. And a plumber had to be called at massive expense, to roto-root it out.
Much as the plumber enjoyed the bi-annual check, we decided to take out the bush, and it was quite a job.
Its now, as far as anyone can see, dead. Nothing above ground.

About 3 months after taking the bush out, the toilets downstairs backed up again. We called the plumber.
He put a snake down, and poked a hole in "something"- took him all of about 3 minutes. He charged us full price, because "you win some you lose some". So that was that. However, the blockage was NOT ROOTS.
We just assumed then, someone had flushed something down the line.

About six months after this, the downstairs toilets backed up again.
This time instead of calling our pricy plumber, I poured a couple bottles of Draino MaxGel Clog down the shower in the downstairs apartment, which goes right to the main line. It sat overnight, and toilets were working.

But it didn't stop there.
A couple days later, toilets backed up again. By the time I got out there though, they were clear.
People downstairs said the toilets "made a big burp and bubbled", and were clear.
I poured another bottle of Draino down.

Again, block up, and again I come out and they're clear, again with the big "Burp".
As you can imagine, I'm not keen to pay a plumber to come out again, when it was practically nothing last time. But these blockups keep happening over and over.
What could possibly be causing it now?

My only supposition is someone is flushing SOMETHING down the line, but of course everyone in the building denies it.
It can't be roots, we know that.
I'm not hip on adding a plumber to the payroll for $200 every couple of days, as this building barely pays for itself to begin with, and I'm not wealthy by any means.
Can anyone help with ideas? I am completely out of them.
:/

Signed,
Pooped Out in 2021

 

[James Henry]

It sounds like it's a partial blockage, wipes, etc. I've encountered this many times. because the drain is partially blocked, when too much water is going down the drain at once, the drain will fill and the water will back up. Once their is no more water going down the drain the drain will slowly empty and the toilet will flush again without backing up until the drain fills up again. Hence the, " by the time I got their they were clear".

 

[Sponsor]

 

[Reach4]

If you have an outside cleanout, I would think that rodding the path would be under $300. What are you paying?

You could get the path checked out with a camera. This involves cleaning, followed by the camera work.

Or if you have clay sewer, you could get that swapped out for PVC without further checking. Yes, big bucks, but it is the cure.

 

[Jeff H Young]

So its a small building with 3 apartments, which I rent out.

Sorry to hear but the plumber in bottle isn't a genie. Sometimes old buildings 200 a call wont cut it . it could need major work. You may need to get more creative a loan perhaps ? A million dollar property can need 100,ooo in work but if you got no money and cant maintain it tenants don't need to pay you anything and you turn into a the slumlord .
Cold facts your the landlord you must maintain it or dump it. otherwise no one is going to pay rent When you chopped the bush down your pipes didn't get new again.
I think its a problem with the sewer not just a tenant problem

 

[Sylvan]

Why didn't the plumber do a video inspection?

Just because the tree is cut down doesn't mean there is no roots and if the roots did infiltrated the sewer system there had to be an opening that a video would have picked up.

A retrieving head in lieu of a cutting head on the cable should tell if it it was an object such as a sanitary product