In a soup pot on top of the stove add water, potatoes, carrots, celery and onions. Bring to a boil, reduce heat to simmer and cook for 15 minutes or until potatoes and carrots are tender.
In a small saucepan, melt the butter then add in flour, salt and pepper stirring until smooth.
Add milk and bring to a boil stirring constantly until starts to thicken.
Remove from heat and add to soup pot. Stir in corn and Parmesan cheese.
Heat soup on low for about 10 more minutes. This is a thick soup. Makes about 8 servings.
Notes
If using salted butter, cut salt added to 1/2 teaspoon.