Filtering water out of the tap has become nearly ubiquitous. We would all like to assume that the water our town, city or well provides is clean and tasty, but putting it through an extra filtering step that we control seems to make many of us feel safer. However, when the filter gets clogged, "clean" water becomes much more difficult to acquire.
Remove the filter from the pitcher and look closely at the top to see if there are any large pieces of sediment blocking the intake vents. Brush these gently away with the toothbrush and then rinse with tap water. Return the filter to the pitcher and test it to see if water flows more freely through the vents and then out the bottom.
If the flow of water is minimal or continues to be blocked, there may be mineral deposits from your tap water that have built up in the vents. Fill a measuring cup with half a cup of white vinegar. Place the filter, vent side down, into the vinegar and allow it to soak for 30 minutes. Only the end of the filter will be covered with vinegar.
Remove the filter from the vinegar and brush the vents briskly with the toothbrush. Again, rinse the filter and return it to the pitcher. Fill with water to test the flow. If the flow is satisfactory, fill the pitcher several times to cleanse the filter of the vinegar taste. If the filter is still clogged, it should be replaced.