T-filters can keep up with water filtration for about a year or more before they need to be replaced. However, if you’re using water from a pond, canal, or well, you may need to clean and replace the filter more often. During the irrigation season, try to check up on your filters every two to four weeks to ensure that there aren’t any tears, dents, or corrosion in the mesh. If you notice a dip in your irrigation system’s water pressure, it may be a sign that it’s time for a new sprinkler filter screen.