90 yr old house has water line running to house (in backyard flowerbed) with three gate valves. Two are on each side of pipe, and one is on top.
Hear running water behind wall in back of house (pier & beam) and think there might be broken pipe. Need to turn off main supply to house. Which valve is main supply shuttoff and which is bleeder valve or other? Have tried valve closest to house, but still hear water running -- other two will hardly budge.

Hb, shut off all three and if the sound of leak is gone open them one at a time an listen for leak, and check faucets to see what they control. Good luck

Looking at your drawing I'd say the one nearest the alley is the main.