Who is actually allowed to bill you
The city is rarely the only one. In much of the country the largest single charge comes from an entity most buyers have never heard of.
The five layers
A single new house can be billed by: the municipality or county building department, for permit and plan review; the same jurisdiction again, for impact fees; a separate water provider; a separate wastewater provider; and one or more special districts for fire, parks, drainage or schools.
Each layer has its own adopted schedule, its own effective date and its own appeal process. There is no single desk that knows all of them, which is why written estimates from each one is the only reliable method.
Special districts are the blind spot
Metropolitan and sanitation districts levy system development fees under their own authority, on their own timetable, often with rate cards that never appear on the city's site. Published district rate cards in some high-cost regions list single-family water and wastewater system development fees in the tens of thousands of dollars per tap, with reductions for smaller units.
Notice what that last clause implies: some districts scale the charge by dwelling size, and some charge accessory dwelling units at a fraction of a full tap. Those reductions exist in the schedule and are not always offered proactively.
The school district question
School fees are the most jurisdictionally scrambled item in the country. Most state acts do not authorize them at all. Where they exist, they are sometimes levied by the local government and sometimes by the district itself: Hawaii's Department of Education designates school impact districts directly, and Oregon lets districts levy a construction tax capped per square foot.
If you are quoted a school fee in a state whose act does not list schools, that is not necessarily an error. It usually means the charge rests on some other authority. Ask which one.
How to force the complete picture
Ask each department the same closing question: is there any other entity that will bill this project before certificate of occupancy? Staff answer that question honestly and it costs you nothing.
Then compare their answers to the taxing district list on the parcel record. Anything on that list that nobody mentioned is your next phone call.