Cook the bacon until crispy and drain on paper towel; crumble and set aside.
In a large soup pot, add the chicken stock and water. Add in the potatoes, onions and celery and bring to a boil. Turn the heat to medium, add in the quinoa and let the soup simmer for 10 minutes or until potatoes are tender.
Mix the flour and mayonnaise with 1 cup of the half and half. Stir that into the soup (it won't be smooth yet, but don't worry about that). Stir in the other 2 cups of half and half, along with the corn and crumbled bacon.
Bring the soup back up to a light boil and let simmer for a few minutes. Remove from heat and top with shredded cheddar and green onions. Serve immediately.