Luckily, both the cause and the solution to this problem are incredibly simple. If you are getting water collecting in the bottom of your fridge or around the salad bin area, it’s almost certainly due to the drain hole being blocked.
The drain hole can be found on the back wall of the of the fridge. Clearing the hole should just need a couple of pokes with the small plunger (this should be kept in the hole).
If the issue is still not resolved, the blockage may just be a bit further down. Use a pipe cleaner in order to reach any deeper blockages.
Try not to let any food or produce you put into the fridge touch the wet back wall. Not only can this cause drain hole blockages but it can also allow water to bypass the hole completely, and drain into your food instead.