Water and Sewer Bill Breakdown: Fixed Charges, Usage, and Tiers

Start a water-bill audit by identifying the meter unit and billing days. A utility may use gallons, cubic feet, or CCF; EPA says one CCF is 748 gallons. Then separate the fixed customer charge from the volumetric water charge and the wastewater charge. EPA’s bill guide explains that utilities commonly combine a base fee with a variable volume fee, while some estimate sewer volume from the water meter.

Copy the bill into a worksheet

Field	What to capture
Meter readings	Previous, current, estimated/actual, and billing days
Water use	Gallons, CCF, or cubic feet; convert only once
Water charges	Customer charge, tiered volume, drought or benefit riders
Sewer charges	Customer charge, volume, caps, winter average, or deduction
Other	Taxes, late fees, credits, and payment-plan adjustments

EPA identifies flat, uniform, increasing-block, declining-block, seasonal, drought, and water-budget rates. Find the exact structure in your tariff before multiplying all gallons by the top tier. A tiered bill charges each block at its own rate; it does not necessarily apply the highest rate to every gallon.

A concrete territory example

Philadelphia Water Department says its September 1, 2026 typical residential bill is $96.16, based on 430 cubic feet of monthly use and a 5/8-inch meter. It separately states that customers are billed for every 100 cubic feet, or 1 CCF. Read the department’s rate notice. That is a Philadelphia example, not a national average or a prediction for another meter size.

For a teaching calculation, assume a bill has a $22 fixed water charge, 6 CCF at $4 per CCF, a $31 fixed sewer charge, 6 CCF at $7 per CCF, and $4 of riders. Water is $22 + (6×$4) = $46; sewer is $31 + (6×$7) = $73; total is $46 + $73 + $4 = $123. If an irrigation meter removes 2 CCF from sewer billing, sewer usage becomes 4 CCF and the example falls to $109. These figures are assumptions.

Why use can move the total twice

With one meter, outdoor water may be counted as both water delivered and wastewater returned. EPA notes that some utilities bill sewer volume from the incoming water meter, while others offer a deduction or separate meter for water that does not enter the sanitary sewer. A leak can therefore increase both lines. Check for running toilets, irrigation leaks, and estimated reads before assuming the tariff changed.

Compare a high-use month with a low-use month and mark the tier boundary crossed. Check seasonal or drought surcharges and whether wastewater uses a winter average or a cap. Fixed charges continue even when use falls, so conservation may reduce only the variable portion. Assistance programs can alter eligible fixed and volumetric lines; record the program separately from the rate.

The next action is to request the current tariff, rate effective date, and a line-by-line explanation for any unfamiliar rider. Keep your worksheet in the bill’s units and convert gallons only when comparing offers. That makes the bill auditable and prevents a per-gallon calculation from hiding fixed sewer costs.