It looks to me that the calculator is expressing the following rental situation: you rent from a landlord that includes for example, water and sewage utilities

It looks to me that the calculator is expressing the following rental situation: you rent from a landlord that includes for example, water and sewage utilities as part of the monthly rental fee. The fair way to account for this rental situation for the equivalent buying scenario is to add the true cost of those utilities to the buying scenario because when you look at buying the equivalent, you will have to pay for those utilities, and thus lengthening the break-even point when compared to renting.