The city of San Diego will let its two firefighting helicopters make nighttime water drops on wildfires outside city limits under an agreement with the county, Mayor Kevin Faulconer and other officials announced Tuesday.

The city’s choppers are the only ones in the region that can make nighttime drops. The deal makes them available for fires on unincorporated county land or within the region’s 17 other cities.

“When a wildfire comes, we have to be focused on results and saving lives, not jurisdictional boundaries drawn on a map,” Faulconer said. “That’s why the city and county are embarking on a new level of cooperation to make sure our region is as prepared as possible for whatever comes our way.”

The current deal took effect Dec. 1 and will run through June 30, 2016. The city and county will have five subsequent option years.

The county will reimburse the city at the rate of about $3,700 an hour for one helicopter and $5,000 an hour for the other.

“The new city-county partnership to extend night flights to all corners of our region is great news for residents and builds on our efforts to bolster fire protection,” said Dianne Jacob, who chairs the San Diego County Board of Supervisors.

“Wildfire is a year-round threat in San Diego County, from our cities to our backcountry, so I want to thank Mayor Faulconer for his leadership on this critical issue,” she said.

Wildfires most recently ravaged northern areas of San Diego County in May, with one spreading from within San Diego city limits to unincorporated land near Rancho Santa Fe. Blazes from the devastating 2003 and 2007 firestorms started in an unincorporated county area and roared into the city of San Diego.

County and municipal officials have been working to improve the coordination of communications and mutual aid ever since those disasters.