Two utilities charging the same price for the same water can produce bills that differ by a factor of three, and none of the difference is the price. A comparable bill has to fix two things utilities do not agree on: how much water, and over what period.
The volume is fixed at 72 hundred cubic feet a year
About 53,900 gallons, or six hundred cubic feet a month, which is a modest household. One number for every system, so the comparison is between prices rather than between customers.
The choice of volume changes who looks expensive. A system with a high fixed charge and cheap water looks expensive at low volumes and cheap at high ones; a steeply tiered system does the reverse. That is a property of rate design, and it is why a high-volume bill is carried too, wherever one can be computed.
The period is a year
Utilities do not share a billing period. Most bill monthly, but a substantial minority bill bi-monthly, quarterly or annually.
A bi-monthly system’s fixed charge is not half a monthly one. Converting between them assumes both usage and tier thresholds scale with the period, and no filing states either. Pricing a year avoids the assumption: each system’s filed structure is evaluated at the volume its own billing period carries, and the year is the sum of those bills. Nothing is scaled and no threshold is stretched. It is the arithmetic the utility itself performs.
An annual figure is also what affordability needs, since income is annual.
Where the bill can be reconciled against a regulator’s own published charge, it matches to the cent. Where it cannot be, it is withheld.
What is not in the bill
The water charge only, unless a page says otherwise. Wastewater is billed by the same utility in some places and a separate authority in others, so including it would make the figure comparable in one town and not the next; where a system files a wastewater charge, it is carried as a separate figure.
Nothing here includes stormwater fees, connection or capacity charges, taxes, or a low-income discount. A discount applies to some households and not others, so a bill net of it is not the bill anybody receives.