It looks like the previous owners had the same problem because there is some damage to the floor there.
Sliding glass door leaking into basement.
Spray the door and look for the leak location.
A sliding glass door is no better than the frame into which it is placed.
One potential problem area you can overlook is underneath an exterior door.
I do not know who installed it.
Look around your walk out basement door to identify where the water is entering.
Fill any cracks around the door with silicone caulking or concrete repair filler.
There is a deck outside above the door and a sliding glass door upstairs directly above the leak.
Use silicone caulking to fill any.
See what we did to repair the situation.
The best way to stop the leaks is to prevent them from occurring in the first place.
1 leakage from poor failed caulk and or flashing over or around the door leaking down to the bottom of the door and then out onto the floor 2 poor seals on the door itself.
If a frame is crooked water can leak into the gaps between door and frame.
The door is a retrofit from a previous owner.
If you cannot re create the leak problem inspect the interior of the door for stains or rust.
First time having a house with a sliding glass door and i m getting water inside.
I ve checked them and they drain properly.
Have a reputable sliding door contractor remove the door if it has not been damaged build a new frame and reinstall the door.
In the case of your door water can get behind the.
The track where the screen sits has weep holes.
Aim a garden water hose with a sprayer set on mist or low at the outside of the sliding door.