| Collection System of the Year | Small (1-249 Miles) | Medium (250-500 Miles) | Large (Over 500 Miles) |
|---|---|---|---|
| 2019 | City of Pacifica | City of Santa Barbara | City of Riverside |
| 2018 |
Castro Valley Sanitary District |
City of Vista |
Coachella Valley Water District |
| 2017 | City of Banning | City of Merced | Santa Rosa Water |
| 2016 | Carpinteria Sanitary District | Cucamonga Valley Water District | LA Sanitation, the City of Los Angeles |
| 2015 | Goleta Sanitary District | City of Merced | Irvine Ranch Water District |
| 2014 | Carpinteria Sanitary District | City of Pomona | City of San Diego |
| 2013 | Fairfield-Suisun Sewer District | Oro Loma Sanitary District | Central Contra Costa Sanitary District |
| 2012 | Costa Mesa Sanitary District | City of Glendale | City of San Diego |
| 2011 | Leucadia Sanitation District | City of Simi Valley | City of Thousand Oaks |
| 2010 | Las Gallinas Valley Sanitary District Small Collection System | Oro Loma Sanitary District | City of Roseville Wastewater Collection |
| 2009 | South Placer Municipal Utility District | Orange County Sanitation District | Union Sanitary District |
| 2008 | Leucadia Water District | Truckee Saznitary District | City of Los Angeles, Department of Public Works, Bureau of Sanitation |
| 2007 | City of Davis Wastewater Collections | Elsinore Valley Municipal Water District | Central Contra Costa Sanitary District |
| 2006 | Leucadia Water District | City of Fullerton | No winner |
| 2005 | City of Foster City | No winner | Union Sanitary District |
| 2004 | Leucadia Wastewater District | Oro Loma Sanitary District | No winner |
| 2003 | Goleta West Sanitary District | No winner | City of San Diego |
| 2002 | Castro Valley Sanitary District | Truckee SD | Central Contra Costa Sanitary District |
| 2001 | Tahoe City Public Utility District | City of Livermore | No winner |
| 2000 | Padre Dam MWD | Oro Loma Sanitary District | Irvine Ranch Water District |
| 1999 | Leucadia Water District | Elsinore Valley MWD | Union Sanitary District |
| 1998 | Big Bear City CSD & City of Foster City | Vallejo Sanitation and Flood Control District | Eastern MWD |
| 1997 | City of Santa Cruz | Truckee SD | No winner |
| 1996 | Goleta Sanitary District | Irvine Ranch District | City of San Diego MWWD |
| 1995 | Cambria Comm. Svcs District | Vallejo S&FCD | Sacramento Co SD No. 1 |
| 1994 | Leucadia County WD | County of San Diego | City of San Diego |
| 1993 | Tahoe City PUD | West Valley SD | Riverside WQCP |
| 1992 | Goleta Sanitary District | County of San Diego | Central Contra Costa SD |
| 1991 | No Winner | Leucadia County WD | City of Los Angeles |
| 1990 | Bayshore SD | City of Modesto | Union Sanitary District |
| 1989 | Tahoe City PUD | City of Palm Springs | City of Stockton |
| 1988 | Napa Sanitation District | City of Turlock | Central Contra Costa SD |
| 1987 | CSD #4 of Santa Clara Co. | City of Daly City | Union Sanitary District |