Basement bathroom branch had a paper stoppage caused byroots collecting paper .

After that tenants pay for all blockages and stoppages which is detailed in the lease. 

Assuming it was operating properly at move in, and dependent on exactly what your Rental Agreement states with regard to plumbing stoppages and/or proper use of fixtures and appliances, yes, you should be able to deduct your actual cost to make it operational.

Curious how the work stoppage played out.

(Often you can "solve" low flow of a hot water faucet by changing any/all elbows you can access from the water heater to that faucet.)So, the short answer to your question is...when repair costs due to plumbing leaks and/or blockages start rising notably, or you are observing several signs of hidden leaks.Once you are past the 25 -30 year mark, you are bound to have more leaks, stoppages, and low flow (as well as prior, poor, repairs).

Yes I have a section in my lease that states tenant is responsible for stoppages and damage that they cause.

We've seen a strong bounce back from the COVID stoppage and the agents/investors I work with are noticing things are still in full gear headed into the beginning of 2021.

Drain stoppages need to be documented by the plumber as to how far out the blockage was, what did they pull back, if anything.

Mike you have what is known as a " Partial Stoppage"In simple language its a "real Stoppage" getting ready to happen.I strongly suggest you get the person responsible for the maintenance of the building to get a video pipe camera inspection of the main sewer line.These symptoms tell me there could be a really big problem down the road if not remedied quickly .Better take the bitter medicine now and fix things than suffer the consiquiences of a major raw sewage backup incident laterDave Doyle.PS Once you sewer line issue is resolved I would reccomend either a Kohler Wellworth or Gerber Avalance Tank Toilet.Very reliable ,,,,,hope this helps,,,DDLos Angeles

Permits be pulled in advance to avoid work stoppage.