Step 1: Go to lAPMO R&T’s Product Listing Directory https://info.nsf.org/Certified/dwtu/
Step 2: Select search category: Listed Model/Additional Company
Step 3: Enter “PP-RWF3500A” in the brand name/model field

Upper Left/Right Corner Filter Housing Installation Instruction
1. Lower the filter housing cover to expose the filter. Pull the old filter downward, twist the filter 1/4  counterclockwise until it releases from the filter receptor, then pull it out.
2. Remove the protective cap from the end of the new cartridge. With the filter’s two top notches in the horizontal position, align with the filter receptor and push it into the receptor, and twist 1/4 clockwise until it stops.

Behind Door-Storage Bin Filter Housing Installation Instruction 
1. Remove the storage bin to expose the filter. Pull up the filter and twist 1/4  counterclockwise  to release the filter. And then pull it out.
2. Remove the  protective  cap from the end of the new cartridge. With the filter’s two top notches in the horizontal position, align with the filter receptor and push it into the receptor, and twist 1/4 clockwise until it stops. Pull the filter inwards. Reinstall the storage bin.

Yes, you must change your LG LT800P refrigerator water filter every 6 months or sooner based on water quality and frequency of use. Failure to change can reduce flow or cause deposits/rust. Overuse reduces performance and may cause leaks.

The reasons for the water leakage may be the following:
1) The O-ring is not in the correct position.
2) Improper installation.

You can try to follow the steps to troubleshoot
1) Please make sure that the black rubber rings on the top of the filter are in the groove.
2) Please try the following installation steps to reinstall it.