Impact fee, tap fee, system development charge: the difference that costs money
They are collected at the same window, on the same day, from the same check. They come from different law, and only one of them is usually protected by your state's act.
The short version
An impact fee pays for the general capital facilities your development burdens: roads, parks, fire stations, sometimes schools. A tap or connection fee pays to join a specific utility system, and typically has two parts: the physical connection, and a capacity charge buying your share of the plant and mains that already exist.
The names blur badly in practice. Oregon calls the whole thing a system development charge. Colorado cities call the utility charge a tap fee and describe it, on their own web pages, as an impact fee. Charleston, South Carolina bills a tap fee and an impact fee as separate lines on the same account.
Why the distinction decides your rights
Most state impact fee enabling acts carve utilities out, or simply never reached them. The Duncan Associates compilation makes the point directly: the absence of water and wastewater from a state's impact fee act does not mean those fees are prohibited, because they are almost certainly authorized under a separate public utility statute.
The consequence is that the refund deadlines, credit requirements and advisory committees your state act guarantees may not apply to the largest charge on your invoice. Utah is a notable exception: its act reaches water and sewer districts explicitly.
Where the money actually is
Industry guidance puts typical tap fees in the range of several thousand to tens of thousands of dollars per connection, driven mostly by meter size and by which utility serves the parcel. Published district schedules in high-cost water regions run well into five figures for a single-family water tap, with wastewater at a similar level.
This is why the sequence in the lookup guide starts with the parcel's district list rather than with the city. In a great many cases the city's impact fee is not the biggest number on the page.
Three questions that save the most money
What meter size does this project actually require? Capacity charges scale with meter size, and an oversized meter is a permanent cost.
Is the main already in the street, or is a line extension needed? Extensions are quoted as contracts, not schedules, and they are the classic budget-breaker.
Did the developer already pay a portion for this lot? In subdivisions where the developer built and donated the mains, connection fees are sometimes waived or reduced for lots inside that development.