Chop the vegetables into small pieces and set aside.
Heat a large stockpot over medium-high heat. Add the olive oil, onions, celery, carrots and green onions and heat for 8-10 minutes, stirring frequently.
Stir in the garlic, parsley, thyme and bay leaves and heat for 1 minute.
IF MAKING VEGETABLE STOCK: Add the water and bring to a rapid boil.IF MAKING VEGETABLE BROTH: Add the peppercorns, salt and water and bring to a rapid boil.
Turn down the heat to medium low and simmer for minutes, uncovered.
Remove from the heat and let cool. Pour the stock through a cheesecloth or strainer, placed over a large bowl, to remove the vegetables and food bits. Discard the solids or store for another use.
Transfer to an airtight container and store for up to 7 days in the refrigerator or up to 6 months in the freezer.
Notes
Note 1- Feel free to use regular tap water if that's what you access to.