According to the article, the tank contained 1.5 million gallons of water.
Capacity of an empty tank is the same as a full tank.
The 1.5 million gal is likely the capacity of the tank. The news video report didn’t mention the current volume or average volume at the time of explosion. From the video, the water is clearly visible falling down and out under the rising tank, and then hitting the ground and pushing outward, moving structures. The video report even used the word “sunami” for the effect of the water on the area immediately around the tank. So that’s why water pressure is low and restrictions are in place—a large volume of water was lost to the ground during the explosion. It will take some time for that to get recycled into the aquifers/wells (geologists—? hundreds of years?), and for the community to pump the well water back into a tank (when they rebuild it or put in a new tank).
Thanks for the info. It appeared to be empty. perhaps it was only partially full - maybe they emptied enough to do the welding. I don’t know any facts about it. But tanks of any kind have a habit of blowing up if you are not careful with your welding.