They sell external filters meant for refrigerators that don't have an internal water filter. You can use those for this purpose too. They are meant to install i

They sell external filters meant for refrigerators that don't have an internal water filter. You can use those for this purpose too. They are meant to install in the water line and are compatible with the connectors commonly used. Search the web for "5-year inline refrigerator water filter" to find some of them.