The 2008 Witch Fire destroyed 1800+ structures and caused over $1.3 billion in damages within San Diego County, CA. There were swimming pools all throughout this fires path of destruction. See the Google Satellite image below.
This shows some of the devastated areas of Rancho Bernardo. The red markers show where 160+ homes were destroyed while the blue markers show where over 450 pools sat full. That’s close to 10 million gallons sitting right where it was needed. Many of these homes likely could’ve been saved.