On October 27, 1993, a fire started near Laguna Canyon Road about one mile north of El Toro Road. Pushed by Santa Ana winds, the fire reached the community of Emerald Bay and entered the perimeter of the District's Moorhead Reservoir. The fire continued north into Crystal Cove State Park and south into Laguna Beach where it reached Park Avenue. By the time it was contained (about 3:30am on Wednesday, October 28), the fire had destroyed 366 homes, damaged over 500 more homes and burned over 17,000 acres of brushland. Approximately 16 million gallons of water over normal usage was needed during the period of the firestorm. This included additional flow to South Coast Water District. The District's water supplier, Metropolitan Water District of Southern California (MWD), supplied all the water the District could take with no flow restrictions. Because of the dry and windy conditions, all reservoirs were filled. Storage within the District was at about 80 percent when the fire entered Laguna Beach. Normal operating levels would have been between 50 percent and 70 percent.

It was extremely difficult to determine exactly how much water was being used at any one time during the fire. However, it was roughly estimated that the peak demand placed on the water system to supply firefighters was approximately 20,000 gallons per minute (gpm). The District also had to contend with broken or melted pipes in burned homes as well as running sprinklers and hoses that were left abandoned when people had to evacuate the area.

The demand on the District's water system was great. In fact, everywhere the fire was being fought, reservoirs were being drained faster than they could be filled. Six of the District's twenty-two reservoirs were completely drained during the fire.

The capabilities of the water system were tested during the firestorm of 1993. As a result of the information gathered during the firestorm, upgrades to the system were implemented to minimize the impact of another such event. Since the 1993 firestorm the District has:

• Updated its master plan to include a goal at fire hydrants of 3,000 gallons per minute at the interface between open space and urban area.
• Built two reservoirs totaling 8 million gallons.
• Purchased additional fixed and portable emergency generators for pump stations.
• Purchased additional portable, large capacity, pumps.
• Installed parallel pipelines in strategic areas for fire flow improvement.
• Identified low pressure areas within the District, some of which (but not all) can be improved.