Probably a partial blockage somewhere even though the water isn't backing up. Snake it out.
snake worked! long story:
today, it was raining and the water did not go down the pipe as seen in the video, or at least the water was not going down fast enough. water leaked in the basement and the only way i knew was i got an alert from the zwave water sensor. of course i did not know anything yet when i got the alert. the water sensor was placed next to the water heater and initially thought the water heater had leaked or something.
went down to the basement and i saw water flowing freely out of the wall where the kitchen pipe ends and where the metal pipe from outside would meet. their junction is somewhere outside, beyond the wall that i saw water flowing in. when i went outside, i saw a big puddle around the metal drain, as seen in the video. thanks to your advice, i went to get an auger from Home Depot. couldnt believe there was a line to go in and a longer line to check out! anywho, i was able to snake the metal pipe clear, for now. too bad i could not grab onto whatever was clogging the pipe and pull it out. i didnt feel any resistance when i was thrusting the snake in either
should i try liquid Draino or am i done for now?
thank you!