We found 175 public water systems that could serve the same population as Thomas Aquinas College (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Oxnard Water Dept | Oxnard | 206,997 | 64 | 5 |
| Ventura Water Department | Ventura | 113,478 | 45 | 2 |
| Ventura Wwd No. 8 - Simi Valley | County of Ventura | 97,292 | 29 | 4 |
| Cal American Water Co | Newbury Park | 61,206 | 49 | 1 |
| Thousand Oaks Water Dept | Thousand Oaks | 53,422 | 48 | 0 |
| Camarillo Water Dept | Camarillo | 47,913 | 74 | 0 |
| Golden State Water Company - Simi Valley | County of Ventura | 43,365 | 71 | 0 |
| Ventura Cwwd No. 1 - Moorpark | Moorpark | 38,703 | 102 | 0 |
| Santa Paula Water System | Santa Paula | 30,752 | 48 | 2 |
| Camrosa Water District | Camarillo | 30,000 | 93 | 2 |
| Port Hueneme Water Dept | Port Hueneme | 21,887 | 46 | 7 |
| California Water Service Co - Westlake | County of Ventura | 19,456 | 48 | 0 |
| Fillmore Water Dept | Fillmore | 15,222 | 62 | 5 |
| Oak Park Water Service | Ventura | 12,200 | 48 | 5 |
| Naval Base Ventura County, Port Hueneme | Point Mugu Nawc | 11,500 | 60 | 5 |
| Casitas Municipal Water Dist | Oak View | 9,992 | 41 | 7 |
| Ojai Water System | County of Ventura | 7,121 | 0 | 2 |
| Channel Islands Beach Csd | County of Ventura | 6,493 | 0 | 0 |
| Camarillo State Hospital | County of Ventura | 6,000 | 0 | 0 |
| Camarillo State Hospital | County of Ventura | 6,000 | 0 | 0 |
| Naval Base Ventura County, Point Mugu | County of Ventura | 5,700 | 0 | 4 |
| Ventura River Water District | County of Ventura | 5,700 | 0 | 2 |
| Pleasant Valley Mutual Water Co | County of Ventura | 5,000 | 0 | 3 |
| Meiners Oaks Cwd | County of Ventura | 4,200 | 0 | 10 |
| Ventura Cwwd No. 19 - Somis | Moorpark | 3,275 | 80 | 0 |
| Rio Mesa High School/oxnard Uhs | County of Ventura | 2,600 | 0 | 1 |
| Warring Water Service Inc | County of Ventura | 2,100 | 0 | 2 |
| Ventura Cwwd No. 17 - Bell Canyon | County of Ventura | 2,049 | 0 | 0 |
| Cal American Wc - Las Posas Estates | County of Ventura | 2,042 | 0 | 0 |
| Crestview Mutual Water Co | County of Ventura | 2,040 | 0 | 3 |
| Nyeland Acres Mutual Water Co | County of Ventura | 2,000 | 0 | 37 |
| Vineyard Avenue Acres Mwc | County of Ventura | 1,820 | 0 | 2 |
| Rio Plaza Water Co Inc | County of Ventura | 1,693 | 0 | 5 |
| Ventura Cwwd No. 38 - Lake Sherwood | Moorpark | 1,527 | 43 | 0 |
| Dempsey Road Mutual Water Co | County of Ventura | 1,520 | 0 | 2 |
| Camarillo Airport Utility | County of Ventura | 1,240 | 0 | 0 |
| Vineyard Ave Estates Mwc | County of Ventura | 1,200 | 0 | 3 |
| Casitas Municipal Water Dist. | Mira Monte | 983 | 0 | 0 |
| Lake Piru Park - Uwcd | County of Ventura | 960 | 0 | 26 |
| Ventura School | County of Ventura | 882 | 0 | 0 |
| Ventura School | County of Ventura | 862 | 0 | 0 |
| Rio Manor Mutual Water Co | County of Ventura | 826 | 0 | 9 |
| Rio School Dist/rio Del Valle School | County of Ventura | 820 | 0 | 5 |
| Senior Canyon Mutual Water Co | County of Ventura | 800 | 0 | 19 |
| Garden Acres Mutual Water Co | County of Ventura | 798 | 0 | 10 |
| Limoneira Ranch #1 | County of Ventura | 760 | 0 | 5 |
| YERBA BUENA WATER COMPANY | County of Ventura | 690 | 0 | 6 |
| Brandeis Bardin Institute | County of Ventura | 600 | 0 | 4 |
| Laguna Vista School/oceanview School Dis | County of Ventura | 600 | 0 | 4 |
| Rancho Sespe Workers Imp Assoc | County of Ventura | 600 | 0 | 5 |
| Rio School Dist/ Rio Real School | County of Ventura | 550 | 0 | 4 |
| Usfs - Wheeler Gorge Campground | County of Ventura | 500 | 0 | 24 |
| Smith Forks Water System | County of Ventura | 500 | 0 | 0 |
| Rancho Sespe | County of Ventura | 500 | 0 | 0 |
| Cloverdale Mutual Water Co. | County of Ventura | 490 | 0 | 3 |
| Strickland Acres | County of Ventura | 429 | 0 | 39 |
| Ocean View School | County of Ventura | 412 | 0 | 0 |
| Raytheon Company | County of Ventura | 400 | 0 | 0 |
| Lake Sherwood | County of Ventura | 400 | 0 | 0 |
| El Rio Mutual Water Company | County of Ventura | 400 | 0 | 0 |
| Saviers Road Mutual Water Co | County of Ventura | 368 | 0 | 9 |
| Fillmore Irrigation Co | County of Ventura | 353 | 0 | 10 |
| Houweling Nurseries, Ltd | County of Ventura | 350 | 0 | 5 |
| Sisar Mutual Water Co | County of Ventura | 340 | 0 | 6 |
| Wilshire Blvd Temple Camps/camp Hess Kra | County of Ventura | 300 | 0 | 0 |
| Camarillo High School | County of Ventura | 300 | 0 | 0 |
| Academy Mutual Water Co | County of Ventura | 300 | 0 | 0 |
| Siete Robles Mutual Water Co | County of Ventura | 274 | 0 | 13 |
| Ranchitos Mutual Water Co | County of Ventura | 267 | 0 | 0 |
| U.s.n., San Nicolas Island | Point Mugu Nawc | 250 | 0 | 11 |
| Vineyard Mutual Water Company/industrial | County of Ventura | 240 | 0 | 4 |
| Casitas Mutual Water Company | County of Ventura | 229 | 0 | 11 |
| Cypress Mutual Water Co Inc | County of Ventura | 217 | 0 | 9 |
| Del Norte Mutual Water Co. | County of Ventura | 201 | 0 | 10 |
| Sam Edwards Assoc | County of Ventura | 201 | 0 | 0 |
| Santa Clara Resources | County of Ventura | 200 | 0 | 20 |
| U S Forest Service | County of Ventura | 200 | 0 | 0 |
| Saticoy Country Club-city Of Ventura | Ventura | 177 | 0 | 0 |
| Valley Trailer Court | County of Ventura | 170 | 0 | 0 |
| Navalair Mobile Home Park | County of Ventura | 160 | 0 | 10 |
| Elkins Ranch | County of Ventura | 150 | 0 | 12 |
| El Rio Service Center | County of Ventura | 150 | 0 | 0 |
| Middle Road Mutual Water Co | County of Ventura | 134 | 0 | 5 |
| Silver Wheel Trailer Park | County of Ventura | 120 | 0 | 0 |
| Christensen Court | County of Ventura | 114 | 0 | 0 |
| Ventura County Water District | County of Ventura | 103 | 0 | 0 |
| Solano Verde Mutual Water Co | Somis | 100 | 0 | 0 |
| Glenview Mobile Park | County of Ventura | 100 | 0 | 0 |
| Dennison Park | County of Ventura | 100 | 0 | 0 |
| Conservation Endowment Fund | County of Ventura | 100 | 0 | 0 |
| Compton Hunting & Fishing Club | County of Ventura | 100 | 0 | 0 |
| Fillmore West Mobile Home Park | County of Ventura | 99 | 0 | 0 |
| Ventura County Water District | County of Ventura | 93 | 0 | 0 |
| Tico Mutual Water Co | County of Ventura | 90 | 0 | 0 |
| Cabrillo Village | County of Ventura | 90 | 0 | 0 |
| Arroyo Mobile Home Park | County of Ventura | 88 | 0 | 0 |
| Oceanaire Mobile Home | County of Ventura | 86 | 0 | 0 |
| Nishi Quality Flowers, Inc. | County of Ventura | 82 | 0 | 0 |
| Ventura Farms | County of Ventura | 80 | 0 | 0 |
| The Ranch At Live Oak | County of Ventura | 80 | 0 | 0 |
| Prototypes Women's Center | County of Ventura | 75 | 0 | 0 |
| YERBA BUENA WATER COMPANY | County of Ventura | 75 | 0 | 0 |
| Plaza Mobile Home Park | County of Ventura | 74 | 0 | 0 |
| Linda Vista Adventist Elementary School | County of Ventura | 70 | 0 | 0 |
| Evergreen Trailer Park | County of Ventura | 70 | 0 | 0 |
| South Mountain Mutual Water Co | County of Ventura | 68 | 0 | 0 |
| Buenaventura Lemon | County of Ventura | 65 | 0 | 0 |
| Hanson Aggregates West | County of Ventura | 60 | 0 | 0 |
| Casa Tropical | County of Ventura | 60 | 0 | 0 |
| Golden Oaks Mobile Estate | County of Ventura | 58 | 0 | 0 |
| Ventura Boyscout Council | County of Ventura | 50 | 0 | 0 |
| Well-pict Berries Ws | County of Ventura | 50 | 0 | 0 |
| Esterina Properties | County of Ventura | 50 | 0 | 0 |
| Circle B Ranch | County of Ventura | 50 | 0 | 0 |
| H & H Oil Tool Company | County of Ventura | 50 | 0 | 0 |
| Usfs - Mcgill Campground | County of Ventura | 50 | 0 | 0 |
| San Cayetano Mutual Water Co | County of Ventura | 46 | 0 | 0 |
| Hermitage Mutual Water Co | County of Ventura | 45 | 0 | 0 |
| New Camp Bartlett | County of Ventura | 40 | 0 | 0 |
| Rissman Mutual Water Co | County of Ventura | 40 | 0 | 0 |
| Santa Clara School | County of Ventura | 39 | 0 | 0 |
| Thermic Mutual Water Co | County of Ventura | 38 | 0 | 0 |
| Community Mutual Water Co | County of Ventura | 36 | 0 | 0 |
| Limoneira Co. - Mckevett | County of Ventura | 36 | 0 | 0 |
| Beedy Street Water System/industrial | County of Ventura | 35 | 0 | 0 |
| Tenby Water System | County of Ventura | 35 | 0 | 0 |
| Channel Islands National Park | County of Ventura | 34 | 0 | 0 |
| Camp Scheideck | County of Ventura | 30 | 0 | 0 |
| Pyramid Flowers | County of Ventura | 30 | 0 | 0 |
| Vulcan Materials Company - Cal Mat | County of Ventura | 30 | 0 | 0 |
| El Rio Processing | County of Ventura | 30 | 0 | 0 |
| Aliso Mutual Water Company | County of Ventura | 30 | 0 | 0 |
| Steckle Park | County of Ventura | 30 | 0 | 0 |
| Emmawood State Beach | County of Ventura | 30 | 0 | 0 |
| Hailwood Inc Water System No. 8-inactive | County of Ventura | 30 | 0 | 0 |
| Santa Monica Mt. Rec Area - Circle X | County of Ventura | 29 | 0 | 0 |
| Krotona Institute | County of Ventura | 26 | 0 | 0 |
| Usfs - Chuchupate Ranger Station | County of Ventura | 26 | 0 | 0 |
| Brownstone Water Co | County of Ventura | 26 | 0 | 0 |
| Lloyd-butler Mutual Water Company | County of Ventura | 25 | 0 | 0 |
| Bouquet Multimedia | County of Ventura | 25 | 0 | 0 |
| State Ready Mix, Inc. | Ventura | 25 | 0 | 0 |
| Waters Road Domestic Users Group | County of Ventura | 25 | 0 | 0 |
| Rincon Water & Road Works | County of Ventura | 25 | 0 | 0 |
| Pine Mountain Inn Water System | County of Ventura | 25 | 0 | 0 |
| White Stallion | County of Ventura | 25 | 0 | 0 |
| Beef Barn | County of Ventura | 25 | 0 | 0 |
| Camp Whittier | County of Ventura | 25 | 0 | 0 |
| Ozena Campground And Station | County of Ventura | 25 | 0 | 0 |
| Chuchupate Campground | County of Ventura | 25 | 0 | 0 |
| Usfs - Hard Luck Campground | County of Ventura | 25 | 0 | 0 |
| U.s.n., Santa Cruz Island | County of Ventura | 25 | 0 | 0 |
| Nps Channel Islands Nat. Park | Santa Barbara I | 25 | 0 | 0 |
| Fuller Falls Mutual Water Co | County of Ventura | 23 | 0 | 0 |
| Teal Club Mutual Water Co | County of Ventura | 18 | 0 | 0 |
| Ahrens Aircraft | County of Ventura | 10 | 0 | 0 |
| Channel Islands National Park | County of Ventura | 10 | 0 | 0 |
| Rio School Dist/ El Rio School | County of Ventura | 9 | 0 | 0 |
| Rca Global | County of Ventura | 8 | 0 | 0 |
| Unocal Water System | County of Ventura | 5 | 0 | 0 |
| Mcgrath | County of Ventura | 5 | 0 | 0 |
| Ventura County Humane Society | County of Ventura | 5 | 0 | 0 |
| Rancho La Cuesta Limited | County of Ventura | 4 | 0 | 0 |
| Owl's Barn Water System | County of Ventura | 4 | 0 | 0 |
| Dale & Francis Bastyne | County of Ventura | 4 | 0 | 0 |
| Port Hueneme Water Agency | County of Ventura | 0 | 0 | 0 |
| United Wtr Cons Dist | County of Ventura | 0 | 0 | 0 |
| Calleguas Municipal Water Dist | County of Ventura | 0 | 0 | 0 |
| Naval Base Ventura County-camarillo Hsg. | County of Ventura | 0 | 0 | 0 |
| Conejo Water System | County of Ventura | 0 | 0 | 0 |
| Sherwin Acres Mutual Water Co | County of Ventura | 0 | 0 | 0 |
| Usfs - Blue Point Campground | County of Ventura | 0 | 0 | 0 |
| Usfs - Lions Canyon Campground | County of Ventura | 0 | 0 | 0 |
| Royal Duke Mobile Estate | County of Ventura | 0 | 0 | 0 |
| Las Posas Orchard/somis Pacific Mgmnt. | County of Ventura | 0 | 0 | 0 |