When we moved into this rental home, our landlord mentioned that he changes the water filter every 2-3 months.  Well, sure enough after 4months of using the filter it was time to change!  The water that come out of the fridge dispenser tasted like garlic towards the end of the glass.  Or maybe it was the ice cubes.  Either way, they both used the same filter.  So, we detached the filter and went to our local home improvement store.  They had a huge selection of PUR water filters and thankfully we were able to find the match to give us good tasting water again.