Recommended maintenance activities for media filters (Sources: WMI, 1997; Pitt, 1997).
Link to this table

Activity Schedule
  • If filter bed is clogged or partially clogged, manual manipulation of the surface layer of sand may be required. Remove the top few inches of media, roto-till or otherwise cultivate the surface, and replace media with like material meeting the design specifications.
  • Replace any filter fabric that has become clogged.
As needed
  • Ensure that contributing area, facility, inlets and outlets are clear of debris.
  • Ensure that the contributing area is stabilized and mowed, with clippings removed.
  • Remove trash and debris.
  • Check to ensure that the filter surface is not clogging (also check after storms greater than about 1”).
  • Ensure that activities in the drainage area minimize oil/grease and sediment entry to the system.
  • If permanent water level is present in pre-treatment chamber (e.g., perimeter sand filter), ensure that the chamber does not leak, and normal pool level is retained.
Monthly
  • Check to see that the filter bed is clean of sediment and the sediment chamber is not more than 6 inches of sediment. Remove sediment as necessary.
  • Make sure that there is no evidence of deterioration, spalling or cracking of concrete.
  • Inspect grates (perimeter sand filter).
  • Inspect inlets, outlets and overflow spillway to ensure good condition and no evidence of erosion.
  • Repair or replace any damaged structural parts.
  • Stabilize any eroded areas.
  • Ensure that flow is not bypassing the facility.
  • Ensure that no noticeable odors are detected outside the facility.
Annually
  • Remove and replace the top 2-5 inches of media every 3 to 5 years for low sediment applications, more often for areas of high sediment yield or high oil and grease
3 to 5 years