Backed up water

[Vito]

Hello there, I am new to this forum. When it rains; water backs up from the grate in front of the basement door.
I snaked it 15 feet no problem found. I just found another cleanout plug in the middle of the basement. Looks like it is in the same line as the drain. A plumber tried with a water hose at full force in front of the basement door, and no backup was seen. Any suggestions are highly appreciated.

 

[breplum]

further in-depth investigation is required. video sewer inspection camera and a smart plumber reveals more than anything else.

 

[Vito]

further in-depth investigation is required. video sewer inspection camera and a smart plumber reveals more than anything else.

 

[Vito]

thanks, I thought of that too.

 

[Geofd]

Could just be ground water when city sewers get overwhelmed the water has no place to go, 15' isn't far enough unless that gets you to the street