What size fire water tank do I need in San Diego County?

Under the 2026 San Diego County Consolidated Fire Code (effective January 1, 2026), the minimum fire water tank size is 7,500 gallons for structures up to 3,600 sq ft, and 15,000 gallons for structures over 3,600 sq ft. These requirements apply when a fire hydrant is not within 625 feet of the structure. Properties with close exposures (adjacent structures within 100 ft) may require substantially more.

When is a fire water tank required in San Diego County?

In San Diego County, a private fire water tank is required when: (1) no fire hydrant is within 625 lineal feet of the closest building corner; (2) the water district cannot provide adequate fire flow even with a waterline extension; or (3) the property is new construction in a WUI area where hydrant access is infeasible. Per CFA #600, a waterline extension is required first if a water main is within 1,500 feet.

What is CFA 600 and how does it affect my fire water tank in San Diego County?

CFA #600 is the San Diego County Fire Authority's Residential Water Tank Standards document, revised April 2, 2026. It governs sizing, installation, outlet placement, and material requirements for private fire water tanks in San Diego County. Key requirements include: tank must be steel (galvanized) or fiberglass-reinforced plastic per NFPA 22; outlet must be 50–150 ft from the structure; and the updated 2026 code nearly doubled prior capacity requirements.

How far does a fire water tank need to be from the house in San Diego County?

Per San Diego County CFA #600, the fire water tank outlet must be located 50 to 150 feet from the protected structure. The tank itself must be accessible to fire apparatus. These requirements ensure fire crews can connect to the tank without obstructions during an emergency.

Did San Diego County increase fire water tank requirements in 2026?

Yes. The 2026 San Diego County Consolidated Fire Code (effective January 1, 2026) nearly doubled the required fire water tank sizes from prior requirements. The previous code required 5,000 gallons for smaller structures and 10,000 gallons for larger ones. The updated code requires 7,500 gallons (structures ≤3,600 sq ft) and 15,000 gallons (structures >3,600 sq ft).

FireWaterTanks → San Diego County

San Diego County
Fire Suppression Water Tank Requirements

Approximately two-thirds of the San Diego region falls within Very High Fire Hazard Severity Zones. The 2026 Consolidated Fire Code — effective January 1, 2026 — nearly doubled tank size requirements, making San Diego County one of the most consequential jurisdictions for fire water storage compliance.

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Requirements

When Is a Water Tank Required in San Diego County?

A private fire suppression water storage tank is required when any of these conditions apply:

No Fire Hydrant Within 625 Feet
If your property cannot be served by a fire hydrant within 625 lineal feet (measured along the driveway/road from the closest building corner to the nearest hydrant), a private water storage tank is required.

Water District Cannot Provide Adequate Fire Flow
A waterline extension is required if a water main is within 1,500 feet of your property. A tank is only authorized when the water district confirms it cannot provide adequate fire flow even with an extension.

New Construction in WUI Areas
All new structures in WUI areas must meet fire flow requirements per the 2026 Consolidated WUI Code (Section 404), including on-site water storage when hydrant access is infeasible.

Exposure Distance ≤ 100 Feet
When adjacent properties are within 100 feet, fire flow — and therefore tank storage — may be increased by the fire code official, potentially requiring substantially larger tanks.

Tank Sizing

San Diego County Tank Size Requirements

Building Size	Flow Rate	Required Tank Capacity	Duration
≤ 3,600 sq ft	250 GPM	7,500 gal	30 minutes
Over 3,600 sq ft	250 GPM	15,000 gal	60 minutes
With close exposure (≤ 100 ft)	500–2,500 GPM	Substantially more	120 min minimum

These are the 2026 code requirements (effective Jan 1, 2026) — a major increase from the prior code which required 5,000/10,000 gallons. Tank sizing assumes NFPA 13D sprinklers are installed. Without sprinklers, sizing is per CFC Appendix B, which can produce substantially higher requirements.

Fire Hazard Zones

VHFHSZ & WUI Zones in San Diego County

Approximately two-thirds of the San Diego region falls within designated Very High Fire Hazard Severity Zones, making WUI code requirements broadly applicable throughout the county's unincorporated areas.

Key Areas Affected

Backcountry communities — Ramona, Julian, Alpine, Descanso, Pine Valley
North County rural areas — Valley Center, Pauma Valley, Palomar Mountain
East County — Lakeside (rural portions), Jamul, Potrero, Campo
Coastal interface — Rancho Santa Fe, Elfin Forest, Harmony Grove

Zone 0 Requirements (New in 2026)

0–5 feet from structure must be free of combustible materials
Effective for new construction: February 2026
Existing homes in VHFHSZ must comply by February 2027
Defensible Space Zones 1 (0–50 ft) and Zone 2 (50–100 ft) requirements continue to apply

Code References

Key Fire Code References for San Diego County

2026 SD County Consolidated Fire Code, Section 507.2.3 / Table 507.2.3 — Residential water tank size requirements
2026 SD County Consolidated WUI Code, Section 404.5.3 / Table 404.5.3 — WUI water supply requirements
CFA #600 — Residential Water Tank Standards (revised April 2, 2026)
CFC Section 507.2.2 — Waterline extension requirement (within 1,500 ft of water main)
CFC Appendix B — Fire flow calculation by construction type and square footage
NFPA 22 — Water Tanks for Private Fire Protection
NFPA 1142 — Water Supplies for Suburban and Rural Fire Fighting (alternative method)
NFPA 13D — Required residential sprinkler standard
NFPA 24 — Private Fire Service Mains (underground piping)
California Public Resources Code §4201–4204 — FHSZ mapping and designation

2025–2026 Updates

Post-2025 Fire Code Updates & New Legislation

San Diego County proactively updated its codes in the 2026 cycle, independent of the LA fires:

2026 tank size requirements nearly doubled — from 5,000/10,000 gal to 7,500/15,000 gal (effective January 1, 2026)
Brand-new 2026 WUI Code (1st edition) — standalone code with dedicated water supply chapter, backup power requirements for pump-dependent systems
Zone Zero effective February 2026 for new construction; existing VHFHSZ homes must comply by February 2027
Updated FHSZ maps — CAL FIRE released new Local Responsibility Area maps in early 2025, potentially reclassifying additional properties into higher tiers
AB 130 — Extends the 2025/2026 code cycle through at least 2031, giving current requirements long-term stability
SB 90 (Seyarto) — Proposed funding for prepositioned mobile water storage and dip tanks in high-fire areas

Commercial & Industrial

Commercial Fire Water Storage Requirements

Commercial properties in hazardous fire areas require 2,500–3,000 GPM minimum fire flow. Backcountry commercial and industrial projects face even stricter requirements, often necessitating dedicated fire water storage tanks of 100,000+ gallons.

We serve commercial, industrial, and institutional clients across the region — from data centers and manufacturing plants to schools, hotels, and healthcare facilities. View our full commercial & industrial fire water storage page →

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Need a Fire Water Tank in San Diego County?

Tank Specialists of California has 30+ years of experience installing fire suppression water storage systems. As an authorized Pioneer Water Tanks dealer, we handle everything — from fire code analysis and permitting to foundation, tank assembly, and final inspection.

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(888) 606-TANK

Tank Specialists of California • CA License #745065 • 27570 Commerce Center Dr, Suite 129, Temecula, CA 92590

San Diego CountyFire Suppression Water Tank Requirements