05/19/2026
BUILDLAB
5 min readSan Diego’s ERCES Standard C-1: A New-Construction Guide
San Diego’s Standard C-1 moved emergency-responder radio coverage to digital thresholds with stricter monitoring — and it can hold your certificate of occupancy. Here is what to plan for during design, not after.
If you are building in the City of San Diego, the bar for emergency-responder radio coverage moved. The city’s ERCES Standard C-1 took effect in 2025 and modernized how in-building public-safety coverage is measured, monitored, and signed off — and because it ties to your certificate of occupancy, it is not a detail you want to discover at final inspection.
What ERCES is, briefly
An Emergency Responder Communication Enhancement System (ERCES, sometimes ERRCS) is the in-building DAS that keeps first-responder radios working deep inside a structure — stairwells, basements, parking, and core areas where signal would otherwise die. Modern construction methods, low-E glass, and below-grade space make coverage gaps the rule, not the exception, which is why the requirement keeps tightening.
What Standard C-1 changed
The headline shift is from analog signal-strength rules of thumb to digital coverage thresholds — measuring the quality metrics a digital radio system actually depends on, not just raw decibels. C-1 also raises the bar on system monitoring, requires labeled and protected secondary power, and reinforces that temporary occupancy will not be granted until coverage is demonstrated. In practice, it means more rigorous design, testing, and documentation than older projects budgeted for.
- Digital coverage thresholds rather than analog signal strength alone.
- Stricter monitoring and supervised, clearly labeled backup power.
- Coverage in critical areas proven before a certificate of occupancy is issued.
- More commissioning and documentation the AHJ will actually check.
Why this is a design-phase decision
ERCES needs riser pathways, antenna locations, a head-end equipment space, and protected power — all things that are cheap to reserve on paper and painful to retrofit into a finished building. A site survey early in design tells you whether you even need a system and, if so, what to set aside. Done late, it becomes field-coordinated rework while you are trying to close out and occupy.
