Water tap or connection fee
A one-time charge to connect to the water system, usually split between the physical tap and a capacity or system development component.
The water utility, which may be a city, a district or a private company
In most states this sits outside the impact fee act entirely, under separate utility authority. It is frequently the largest single fee on a new house.
The charge usually has two components: the physical tap and meter, which is a real cost of work performed, and a capacity or system development component, which buys your share of plant and transmission capacity already in the ground.
Only the second component is arguably an impact fee. Arkansas's act draws exactly this line, folding hook-up and access charges into the impact fee definition unless the charge pays only for the physical connection or recovers the cost of the line being connected to.
Meter size is the single biggest driver. Larger meters carry substantially higher capacity charges, permanently. Size for the actual fixture count, not for comfort.
Where this is authorized
Among the states with a general enabling act, 24 list this facility type as eligible and 5 do not. States without an act are a local question entirely.