In short: a typical monthly water bill is your metered usage times the rate per unit, plus a fixed service charge, plus a sewer charge if your utility bills one separately. U.S. households commonly pay somewhere around $40–$75 a month for water alone, or $70–$100 once sewer is included — enter your own numbers above for a figure that matches your actual bill.
This is a planning estimate built from the charges you enter. Your utility's bill, with its exact rate schedule and any taxes or surcharges, is the true measure.
How the bill is calculated
A residential water bill is almost always the sum of a few separate charges: how much water you used multiplied by the price per unit, a fixed charge that applies no matter how much you use, and often a sewer or wastewater fee layered on top.
total = (usage × rate) + fixed service charge + sewer charge (+ other fees)
If your utility uses a block rate, usage up to the allowance is billed at the base rate and usage above it is billed at the overage rate; the calculator's advanced section handles one such tier.
Worked example. With the calculator's defaults — 6 CCF (4,488 gallons) at $4.50 per CCF, a $12.00 base service charge and an $18.00 flat sewer fee — the water charge is $27.00, and the total comes to $57.00 for the month: $27.00 + $18.00 + $12.00. That works out to about $6.02 per 1,000 gallons, or roughly six-tenths of a cent per gallon.
Common billing units
Check a recent bill to see which unit your utility uses before you enter a rate — mixing up CCF and 1,000 gallons will throw the estimate off by about 34%.
| Unit | Also called | Gallons per unit |
|---|---|---|
| CCF (100 cubic feet) | "Hundred cubic feet," the most common U.S. unit | 748 |
| 1,000 gallons | "kgal" or "unit" | 1,000 |
| 1 cubic meter (m³) | Common outside the U.S. | 264.17 |
| 1 gallon | — | 1 |
What's usually on a water bill
Every utility sets its own rates, so treat these as a starting range for sanity-checking your own numbers, not a rule.
| Component | Typical monthly range | Notes |
|---|---|---|
| Base / fixed service charge | $5–$25 | Often scales with meter size; charged even at zero usage |
| Volumetric (usage) charge | $2–$8 / CCF ($3–$11 / kgal) | The usage-driven part of the bill; may be tiered |
| Sewer / wastewater charge | Often similar to or above the water charge | Frequently billed on the same metered usage |
| Stormwater / other fees | $0–$10 | Not charged by every utility |
Ranges reflect national rate surveys and vary widely by location and utility. Check your provider's published rate schedule for exact figures.
Worked examples
Small apartment
$42.60 / mo
3 CCF (2,244 gal) at $5.20/CCF, $9.00 base charge, sewer billed at $6.00/CCF on the same usage: $15.60 + $18.00 + $9.00.
Typical single-family home
$57.00 / mo
The calculator's defaults: 6 CCF (4,488 gal) at $4.50/CCF, $12.00 base charge, $18.00 flat sewer fee.
High use, tiered rate
$84.00 / mo
12 CCF, 6 CCF allowance at $4.00/CCF then $7.50/CCF beyond it, plus a $12.00 base charge and $3.00 stormwater fee, no separate sewer: $24.00 + $45.00 + $15.00.
Why the rate structure changes the answer
Flat vs. tiered rates. A flat rate charges the same price for every unit you use, so the bill scales in a straight line with usage. A tiered or block rate instead raises the price once you pass an allowance, which rewards conservation and tends to hit high outdoor water users the hardest in summer.
Why sewer is usually tied to water use. Utilities can meter what comes into your home but almost never what leaves it, so most estimate wastewater volume from your metered water use — either as a flat fee or a rate applied to usage. Because outdoor watering never reaches the sewer system, some utilities cap the sewer charge at your average winter usage, when outdoor use is close to zero.
Fixed charges don't move with usage. The base service charge and any stormwater or meter fees appear on every bill regardless of consumption, which is why a household with near-zero usage still owes something every month.
What else affects your real bill
Seasonal and drought rates. Some utilities raise the volumetric rate in summer months or during drought restrictions, and add conservation surcharges once usage crosses a threshold.
Minimum bills. Many utilities charge a minimum amount that includes a small usage allowance, so very low usage doesn't necessarily mean a very low bill.
Taxes and franchise fees. Some municipalities add a utility tax or franchise fee as a percentage on top of the water and sewer charges, which this calculator doesn't include by default — add it to "other fixed fees" as a dollar amount if yours applies.
Private wells and septic systems. Homes on a private well typically pay no water bill at all, and homes on septic usually avoid a sewer charge, so this calculator mainly applies to metered municipal or utility-district connections.
To dig into just one part of the bill, try the water cost per gallon calculator or the sewer bill calculator.
Frequently asked questions
How is a monthly water bill calculated?
Most residential water bills combine three things: a volumetric charge (your metered usage multiplied by the rate per unit), a fixed monthly service charge that doesn't depend on usage, and often a separate sewer or wastewater charge. Some utilities also add small fixed fees for stormwater management or meter maintenance.
What's the difference between CCF and 1,000 gallons?
A CCF is 100 cubic feet, which equals 748 gallons — it's how many U.S. utilities bill because water meters historically measured cubic feet. 1,000 gallons (sometimes called a "kgal" or "unit") is a separate, simpler billing unit some utilities use instead. Check your bill to see which one your utility uses before comparing rates.
Why do I have a sewer charge on my water bill?
Utilities generally can't meter what goes down the drain, so most estimate wastewater volume from your metered water use instead — either as a flat monthly fee or a rate applied to the same usage. Some utilities cap the sewer charge using your average winter usage, since that's assumed to be mostly indoor water that returns to the sewer system.
What is a tiered (block) water rate?
A tiered or block rate charges a lower price for usage up to a set allowance, then a higher rate for usage beyond it, to encourage conservation. This calculator supports one allowance-and-overage tier for a quick estimate; for rate schedules with several blocks, use the water rate tier calculator instead.
Why did my bill jump even though I didn't use more water?
Fixed service charges, sewer fees and other flat charges appear on your bill whether or not your usage changes, and utilities periodically raise rates to cover infrastructure and treatment costs. A jump with unchanged usage usually points to a rate increase, a new fee, or a billing-period change rather than higher consumption.
Sources & references
- U.S. Environmental Protection Agency (EPA). WaterSense: Statistics and Facts.
- American Water Works Association (AWWA). Water and Wastewater Rate Survey.
- Bluefield Research / Circle of Blue. Municipal water and wastewater price surveys.
Sarah Bennett, MS
Water Quality & Sustainability Specialist · Portland, Oregon
Environmental scientist (MS, Water Resources) with 9+ years in residential water quality, treatment, and usage efficiency, and 150+ completed assessments. Sarah writes and reviews the treatment, usage, and cost calculators on watercalculator.us. Read full bio
MS Environmental Science, Water Resources (2018) · BS Environmental Engineering (2016)