California Soil Drainage Rankings

California

How well does the soil drain across California? We ranked every USDA survey area by the percentage of land classified as "well drained." Areas at the top of the list have soils where water moves through at a healthy rate — favorable for building, septic, and gardening. Areas at the bottom have more waterlogged or slowly-draining soils that may require engineered solutions.

The best-drained survey area is Central Sierra Foothills Area, California, Parts of Calaveras and Tuolumne Counties at 98% well-drained soils. The most drainage-challenged is Colorado Desert Area, California at 6%.

#Survey AreaWell DrainedPoorly DrainedDominant Class
1 Central Sierra Foothills Area, California, Parts of Calaveras and Tuolumne Counties 98% 0% Well drained
2 Mariposa County Area, California 98% 0% Well drained
3 Redwood National and State Parks, California 96% 1% Well drained
4 El Dorado Area, California 94% 0% Well drained
5 Los Angeles County, California, West San Fernando Valley Area 93% 0% Well drained
6 Humboldt and Del Norte Area, California 92% 2% Well drained
7 Nevada County Area, California 91% 0% Well drained
8 San Luis Obispo County, California, Carrizo Plain Area 90% 1% Well drained
9 Lassen Volcanic National Park, California 90% 3% Well drained
10 Six Rivers National Forest Area, California 89% 1% Well drained
11 Modoc National Forest Area, California 89% 0% Well drained
12 Eastern Santa Clara Area, California 88% 3% Well drained
13 Mendocino County, Western Part, California 87% 4% Well drained
14 Kern County, California, Northwestern Part 87% 4% Well drained
15 San Luis Obispo County, California, Paso Robles Area 87% 0% Well drained
16 Los Padres National Forest Area, California 86% 0% Well drained
17 Surprise Valley-Home Camp Area, California and Nevada 86% 6% Well drained
18 Placer County, California, Western Part 85% 4% Well drained
19 Stanislaus County, California, Western Part 85% 4% Well drained
20 Inyo National Forest, Eastern Part, California and Nevada 85% 0% Well drained
21 San Mateo County, Eastern Part, and San Francisco County, California 85% 9% Well drained
22 Tehama County, California 85% 0% Well drained
23 San Benito County, California 85% 4% Well drained
24 Klamath National Forest Area, Parts of Siskiyou County, California, and Jackson County, Oregon 84% 0% Well drained
25 Humboldt County, South Part, California 83% 1% Well drained
26 Inyo County Area, California 83% 0% Well drained
27 Lassen National Forest, California, Parts of Lassen, Plumas, Butte, Shasta, and Siskiyou Counties 82% 1% Well drained
28 Humboldt County, Central Part, California 82% 9% Well drained
29 Trinity County, California, Weaverville Area 81% 0% Well drained
30 Modoc County, California, Alturas Area 81% 13% Well drained
31 Tulare County, California, Central Part 81% 0% Well drained
32 Coleville-Bridgeport Area, Parts of Alpine and Mono Counties, California 81% 11% Well drained
33 Alameda Area, California 80% 4% Well drained
34 Shasta-Trinity National Forest Area, Parts of Humboldt, Siskiyou, Shasta, Tehama, and Trinity Counties, California 80% 0% Well drained
35 Santa Clara Area, California, Western Part 80% 8% Well drained
36 Amador Area, California 79% 0% Well drained
37 San Mateo Area, California 79% 2% Well drained
38 Antelope Valley Area, California 78% 0% Well drained
39 Kern County, California, Southwest Part 78% 9% Well drained
40 Santa Monica Mountains National Recreation Area 77% 1% Well drained
41 Stanislaus County, California, Northern Part 77% 1% Well drained
42 Susanville Area, Parts of Lassen and Plumas Counties, California 75% 5% Well drained
43 Mendocino County, Eastern Part and Southwestern Part of Trinity County, California 75% 2% Well drained
44 Ventura Area, California 75% 12% Well drained
45 Los Angeles County, California, Southeastern Part 75% 9% Well drained
46 High Sierra Area, California 74% 0% Well drained
47 Siskiyou County, California, Central Part 74% 6% Well drained
48 Shasta County Area, California 74% 0% Well drained
49 Channel Islands Area, California, Parts of Santa Barbara and Los Angeles Counties 74% 0% Well drained
50 Kern County, Northeastern Part, and Southeastern Part of Tulare County, California 72% 1% Well drained
51 Plumas National Forest Area, California 72% 1% Well drained
52 Intermountain Area, Parts of Lassen, Modoc, Shasta, and Siskiyou Counties, California 71% 9% Well drained
53 Monterey County, California 71% 1% Well drained
54 Tahoe National Forest Area, California 70% 2% Well drained
55 Mendocino National Forest Area, California 69% 0% Well drained
56 Yuba County, California 68% 4% Well drained
57 Fish Lake and Deep Springs Valleys Area, California 67% 1% Well drained
58 Sonoma County, California 66% 8% Well drained
59 Kern County, California, Southeastern Part 66% 0% Well drained
60 Lake County, California 65% 2% Well drained
61 Santa Barbara County, California, South Coastal Part 65% 2% Well drained
62 National Training Center, Fort Irwin, California 64% 0% Well drained
63 Glenn County, California 64% 16% Well drained
64 Eastern Fresno Area, California 64% 16% Well drained
65 Napa County, California 63% 10% Well drained
66 Toiyabe National Forest Area, California 62% 1% Well drained
67 Marin County, California 62% 13% Well drained
68 Fresno County, California, Western Part 62% 18% Well drained
69 Pinnacles National Monument, California 62% 0% Well drained
70 Contra Costa County, California 62% 18% Well drained
71 Stanislaus National Forest, California, Parts 61% 0% Well drained
72 San Luis Obispo County, California, Coastal Part 61% 1% Well drained
73 Madera Area, California 61% 10% Well drained
74 Santa Cruz County, California 60% 7% Well drained
75 Western Riverside Area, California 57% 3% Well drained
76 Eldorado National Forest Area, California, Parts of Alpine, Amador, El Dorado, and Placer Counties 57% 0% Well drained
77 Northern Santa Barbara Area, California 56% 3% Well drained
78 Yolo County, California 56% 32% Well drained
79 Colusa County, California 55% 29% Well drained
80 Butte Valley-Tule Lake Area, California, Parts of Siskiyou and Modoc Counties 54% 29% Well drained
81 Palo Verde Area, California 53% 0% Well drained
82 Merced County, California, Western Part 53% 41% Well drained
83 Sierra National Forest Area Parts of Fresno, California 53% 0% Well drained
84 Eastern Stanislaus Area, California 53% 6% Well drained
85 San Bernardino County, California, Mojave River Area 52% 0% Well drained
86 San Diego County Area, California 51% 1% Well drained
87 Orange County and Part of Riverside County, California 51% 12% Well drained
88 Butte Area, California, Parts of Butte and Plumas Counties 47% 30% Well drained
89 Sequoia National Forest Parts of Fresno, Kern and Tulare Counties, California 45% 0% Well drained
90 Death Valley National Park Area, California and Nevada 45% 0% Somewhat excessively drained
91 Solano County, California 44% 26% Well drained
92 Sierra Valley Area, California, Parts of Sierra, Plumas, and Lassen Counties 44% 32% Well drained
93 Edwards Air Force Base, California, Parts of Kern, Los Angeles, and San Bernardino Counties 42% 0% Well drained
94 Tulare County, Western Part, California 42% 18% Well drained
95 Benton-Owens Valley Area Parts of Inyo and Mono Counties, California 42% 10% Well drained
96 Kings County, California 40% 42% Well drained
97 Sequoia and Kings Canyon National Parks, California 40% 1% Somewhat excessively drained
98 Angeles National Forest Area, California 38% 0% Somewhat excessively drained
99 Merced Area, California 38% 20% Well drained
100 Mojave Desert Area, West Central Part, California 38% 0% Somewhat excessively drained
101 Mojave National Preserve Area, California 36% 0% Somewhat excessively drained
102 Alameda County, California, Western Part 35% 51% Well drained
103 Mojave Desert Area, Northwest Part, California 35% 0% Somewhat excessively drained
104 San Bernardino County Southwestern Part, California 34% 7% Somewhat excessively drained
105 San Joaquin County, California 31% 37% Well drained
106 Marine Corps Air Ground Combat Center at Twentynine Palms, California 31% 0% Somewhat excessively drained
107 Tahoe Basin Area, California and Nevada 29% 6% Somewhat excessively drained
108 San Bernardino National Forest Area, California 29% 0% Somewhat excessively drained
109 Mojave Desert Area, Northeast Part, California 28% 0% Somewhat excessively drained
110 Joshua Tree National Park, California 26% 0% Somewhat excessively drained
111 Sutter County, California 26% 38% Moderately well drained
112 Sacramento County, California 24% 27% Moderately well drained
113 Anza-Borrego Area, California 18% 2% Somewhat excessively drained
114 Riverside County, Coachella Valley Area, California 16% 5% Somewhat excessively drained
115 Inyo National Forest, Western Part, California 14% 2% Somewhat excessively drained
116 Mojave Desert Area, California 10% 0% Somewhat excessively drained
117 Imperial County, California, Imperial Valley Area 9% 39% Somewhat poorly drained
118 Yosemite National Park, California 6% 0% Somewhat excessively drained
119 Colorado Desert Area, California 6% 0% Somewhat excessively drained

See also: national drainage rankings | California gardening soil rankings | all California survey areas