SDMS responds to nearly 100,000 medical emergency calls annually in the city of San Diego and County Service Area (CSA) 17, which encompasses Del Mar, Solana Beach, Encinitas, Elfin Forrest, 4S Ranch and the community of Rancho Santa Fe. 

SDMS has provided 911 emergency services to the city of San Diego since 1997 and to CSA 17 since 2001, which makes it the longest running ambulance provider in each area. With more than 550 employees and a fleet of more than 80 ambulances, SDMS is the largest ambulance provider in the region.