We know that this is long term leakage, because of the following:

 

When the leak was excavated, tree roots had to be cut free from wrapping around the water main. For many years they had been growing and seeking the source of the water which help supply water to the large tree.

 

Note the 1” rock backfill material. The water was traveling through this backfill to a nearby storm sewer.

 

Seven years had elapsed between leak detection surveys. Estimated size of the leak was 12 gallons per minute.