3,298,799 people (2024 Census estimate, −0.1% since 2020)
4,210 square miles of land · 783 people per square mile
“Highest” and “lowest” are just order, not grades: a high rank for poverty or hazard losses means more of it. Each figure's source is in its section below.
82 active community water systems list San Diego County in the area they serve, reporting 3,447,396 people served in all (a system that crosses county lines counts its whole population).
| SAN DIEGO, CITY OF surface water · local government · CA3710020 | 1,408,937 served |
| HELIX WATER DISTRICT surface water · local government · CA3710010 | 277,918 served |
| OTAY WATER DISTRICT buys surface water · local government · CA3710034 | 242,155 served |
| SWEETWATER AUTHORITY surface water · local government · CA3710025 | 184,915 served |
| OCEANSIDE, CITY OF buys surface water · local government · CA3710014 | 174,340 served |
| ESCONDIDO, CITY OF surface water · local government · CA3710006 | 137,044 served |
| VISTA IRRIGATION DISTRICT surface water · local government · CA3710027 | 134,501 served |
| VALLECITOS WD buys surface water · local government · CA3710002 | 114,700 served |
Source: U.S. EPA Safe Drinking Water Information System (SDWIS), active community systems, . Look up any system's violations and test results with EPA's search using its ID.
About 4,414 people were held in San Diego County's jail, in Vera's latest figure (2025). In 2020 it was about 4,832.
Source: Vera Institute of Justice, Incarceration Trends (built from federal Bureau of Justice Statistics jail surveys). Counties without their own jail, or that share one, may show no figure.
42 school districts have their office in San Diego County. School taxes are usually the largest part of a property tax bill.
Spent $2.7 billion — $2 billion to run schools, about $20,783 per student, plus $601.5 million on buildings and equipment. Money in: $1.7 billion local (mostly property tax), $927.7 million state, $390.7 million federal. Long-term debt: $5.5 billion.
Spent $634.4 million — $553.4 million to run schools, about $15,327 per student, plus $36.1 million on buildings and equipment. Money in: $255.3 million local (mostly property tax), $460.8 million state, $93.7 million federal. Long-term debt: $457.6 million.
Spent $588 million — $527.9 million to run schools, about $15,127 per student, plus $26.9 million on buildings and equipment. Money in: $347.8 million local (mostly property tax), $298.4 million state, $29.2 million federal. Long-term debt: $1.1 billion.
Spent $507.6 million — $450.1 million to run schools, about $15,904 per student, plus $44.3 million on buildings and equipment. Money in: $226.9 million local (mostly property tax), $326.3 million state, $63.6 million federal. Long-term debt: $418.2 million.
Spent $344.1 million — $285.6 million to run schools, about $14,622 per student, plus $34.8 million on buildings and equipment. Money in: $145.8 million local (mostly property tax), $216.8 million state, $22.1 million federal. Long-term debt: $430.3 million.
Spent $403.6 million — $331.7 million to run schools, about $17,624 per student, plus $49.7 million on buildings and equipment. Money in: $152.8 million local (mostly property tax), $252.2 million state, $44.7 million federal. Long-term debt: $306 million.
Spent $397.1 million — $306.8 million to run schools, about $18,330 per student, plus $54.1 million on buildings and equipment. Money in: $220 million local (mostly property tax), $200.5 million state, $39.3 million federal. Long-term debt: $820.9 million.
Spent $312 million — $290.6 million to run schools, about $17,631 per student, plus $8.2 million on buildings and equipment. Money in: $95.7 million local (mostly property tax), $241.6 million state, $46.8 million federal. Long-term debt: $174.8 million.
And 34 more.
Source: U.S. Census Bureau, 2023 Annual Survey of School System Finances. Districts are listed by the county of their main office; some serve neighboring counties too.
Source: County Health Rankings & Roadmaps 2025 (University of Wisconsin Population Health Institute), which gathers federal data (CDC, Census, and others); measures cover different recent years. Blank lines aren't reported for small counties.
Overall risk: Very High compared with other U.S. counties. FEMA estimates natural hazards cost San Diego County about $1.5 billion a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very Low; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
1,632 bridges in San Diego County: 869 in good condition, 724 fair, and 39 poor (2.4%). “Poor” means a main part — the deck, the beams, or the supports — is rated 4 or lower on the federal 0–9 scale. It doesn't mean unsafe to drive; unsafe bridges are closed.
| INTERSTATE 805 over TELEGRAPH CANYON DRAIN · built 1971 | 250,000 vehicles a day |
| INTERSTATE 5 over RTE 163 CONNECTORS · built 1961 | 199,000 vehicles a day |
| INTERSTATE 5 over DE ANZA OFF-RAMP · built 1954 | 101,500 vehicles a day |
| INTERSTATE 5 over BATIQUITOS LAGOON · built 1965 | 98,500 vehicles a day |
| INTERSTATE 5 over BATIQUITOS LAGOON · built 1965 | 98,500 vehicles a day |
| INTERSTATE 5 SB over NCTD BNSF & AMTRAK SCRRA · built 1967 | 96,000 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $2.3 billion of work in San Diego County in fiscal 2025, about $686 per resident — to the county, cities, schools, hospitals, nonprofits and others.
Source: USAspending.gov, grants by place of performance, fiscal 2025 (Oct. 2024 to Sept. 2025). Search it by county to see each award.
From Grants.gov: posted grants listing county governments as eligible, soonest deadline first; research-only and overseas programs left out; list updated 2026-10-13, refreshed weekly. 62 are open in all. Cities, towns, school districts and nonprofits have their own lists there.
General election: Tuesday, November 3, 2026. Ballots mailed; drop boxes open: 2026-10-05. Last day to register to vote: 2026-10-19. Early in-person voting: 2026-10-24 to 2026-11-03. Election Day: 2026-11-03. Last day for mailed ballots to arrive: 2026-11-10.
Source: California Secretary of State — Nov. 3, 2026 key dates · California Official Voter Information Guide — dates to remember · California Secretary of State — make a plan to vote
The budget, property tax rates, audits, local officials and offices for San Diego County come from the county's own records, which we haven't gathered — not gathered, never hidden. See what a full county site looks like, or ask to have San Diego County built: brayden.ozark@gmail.com.
More of California: the state government and every county in California.
Nearby counties: Riverside County (66 mi) · Orange County (73 mi) · Imperial County (82 mi) · Los Angeles County (118 mi) · San Bernardino County (131 mi) · Ventura County (165 mi).