Melt butter in large pot over medium-high heat. Add flour and stir to combine, cook for a minute stirring. Add 1 cup water, stir until completely smooth. Add the rest of the water and milk, stir to combine.
Add in the herbs (if desired), pasta, salt. Cook, stirring occasionally, until mixture comes to a simmer. Reduce to med-low heat, and cook, stirring occasionally, for 9-10 minutes. Remove from heat, stir in cheeses to melt. Add salt, pepper, and other ingredients like bacon bits or pieces of ham as desired.