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Stormwater Services and Information for King County, Washington

Multifamily and Commercial Drainage Facility

Maintenance Checklist

Directions for property owner/manager or maintenance vendor:

  1. Refer to the component definitions in the "Drainage Maintenance Standards" booklet, as well as your individual site plan to determine what facilities you have on your property. On a site plan, "CB" refers to catch basin.
  2. Check "yes" or "no" indicating whether you have each facility component on your property (i.e., pond, Type II catch basin, culvert, etc.).
  3. Inspect each component to determine whether it has any defects causing it to not meet the King County standard (see "Drainage Maintenance Standards" booklet).
  4. In the "Meets Standard or Defect Number" column, list the applicable defect number (A-1, A-2, etc.) from the Drainage Maintenance Standards booklet, or write "Meets Standard" if the facility meets the standard. (NOTE: If there is more than one component for a facility type, list each component by its number on the site plan (CB-1, CB-2, etc.) along with any defect numbers.
  5. Perform maintenance on all defective facility components to bring them up to standard.
  6. Check off the work that has been completed and the date it was completed.
  See "Maintenance Standards" booklet for definitions Do you have this facility component on your property? Any defects? List the defect # from the booklet; or write "Meets Standard." WORK COMPLETED
FACILITY TYPE COMPONENT YES NO MEETS STANDARD OR DEFECT NUMBER X DATE

Retention/Detention (R/D)

1.   R/D Pond
Definition: Natural or man-made depression used to store runoff. May be enclosed by a fence. Fills when storm events occur. May not have visible inlet/outlet. May drain by infiltration only (i.e., soak into soil). 		A. Type I Catch Basin (Inlet)          
B. Type 11 Catch Basin (Control Manhole)          
C. Flow Restrictor (located in Control Manhole)          
D. Debris Barrier          
E. Energy Dissipater          
F. Pipe          
H. Fencing (Including Gate)          
I. Access Road          
J. Other-Specific to R/D Ponds          
2. R/D Tank
Definition: Underground large-diameter pipe used to store runoff. Usually has access at both ends. Larger one may have intermediate accesses through Type Il catch basin(s)/manhole(s). Visible access may be through 36" diameter reducer. 		A. Type I Catch Basin (Inlet)          
B. Type II Catch Basin (Control Manhole)          
C. Flow Restrictor (located in Control Manhole)          
D. Debris Barrier          
E. Energy Dissipater          
F. Pipe          
G. Ditch          
L. Access Road          
K. Other - Specific to R/D Tanks          
3.  R/D Vault
Definition: Underground runoff storage area. Concrete precast or poured in place. Usually has access in corners and is normally a large-scale storage facility.		 B. Type II Catch Basin (Control Manhole)          
C. Flow Restrictor          
D. Debris Barrier          
E. Energy Dissipater          
I. Access Road          

 

  See "Maintenance Standards" booklet for definitions Do you have this facility component on your property? Any defects? List the defect # from the booklet; or write "Meets Standard." WORK COMPLETED
FACILITY TYPE COMPONENT YES NO MEETS STANDARD OR DEFECT NUMBER X DATE

Conveyance

4.  Conveyance
Definition: Culvert(s), pipe(s), ditch(es), catch basin(s), and manhole(s) that pick up and convey runoff from buildings and parking areas to one of the above R/D facilities.		 A. Type I Catch Basin (inlet)          
B. Type II Catch Basin (Control Manhole)          
D. Debris Barrier          
E. Energy Dissipater          
F. Pipe          
G. Ditch          

 

  See "Maintenance Standards" booklet for definitions Do you have this facility component on your property? Any defects? List the defect # from the booklet; or write "Meets Standard." WORK COMPLETED
FACILITY TYPE COMPONENT YES NO MEETS STANDARD OR DEFECT NUMBER X DATE

Water Quality

5.  Wet Vault
Definition: Underground water storage area, concrete precast or poured in place, that removes pollutants from runoff through settling action. Usually has access in comers. Will always have standing water and usually has divider baffles.		 B. Type II Catch Basin (Control Manhole)          
C. Flow Restrictor          
D. Debris Barrier          
E. Energy Dissipater          
H. Fencing (including Gate)          
I. Access Road          
L. Other-Specific to Wet Vaults          
6.  Bioswale
Definition: Broad open channel that is lined with grass vegetation, which acts as a filter to remove pollutants from runoff. Usually trapezoidal with flat bottom.		 G. Ditch-Check Dam Sedimentation Only (G-5)          
M. Other-Specific to Bioswales          
7. Wet Pond
Definition: Natural or man-made depression; may be enclosed by a fence. It is similar to a r/d pond. Multi celled, with continually standing water. Removes pollutants from runoff through settling action. If it is a combined r/d and wet pond, the water level will fluctuate during storm events.		 A. Type I Catch Basin (inlet)          
B. Type II Catch Basin (Control Manhole)          
C. Flow Restrictor (located in Control Manhole)          
D. Debris Barrier          
E. Energy Dissipater          
F. Pipe          
H. Fencing (including Gate)          
I. Access Road          
N. Other-Specific to Wet Ponds          

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