Billing Calculator

Four Rivers Sanitation Authority (FRSA) receives water usage information (flow) for metered customer accounts from various water departments throughout Winnebago county. Well accounts, which are not metered, use an average flow based on metered accounts that have similar property usage. For instance, a one-family well account’s flow is calculated from the average flow of metered one-family accounts.

FRSA routinely samples and analyzes waste water from commercial, industrial and government facilities. This analysis determines the Waste Water Characteristics (WWCs) that will be used for bill calculations. The WWCs for residential accounts are determined by annual group sampling and analysis. The items that make up the WWCs are: Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS), Ammonia (NH4) and Phosphorus (PHO). FRSA customers’ bills are calculated by multiplying flow and the concentrations of each of the WWC items by the current FRSA billing rate.

On this page, you’ll find our Sewer Billing Calculator to help you estimate your next bill.

PLEASE NOTE: the bill calculator is for the estimating of RESIDENTIAL customers only, and is NOT an exact billing amount. For bill questions regarding commercial customers, contact Customer Service at 815-387-7500 or email.

After using the calculator, if you wish to make comments or have any questions, please tell us about your experience using the calculator.

Billing Calculator

Instructions: Provide the information requested below, then press “Estimate Bill”. Your Water Flow can be found on your water bill.


2022 Rate Adjustment

Effective April 1, 2022, Four Rivers Sanitation Authority (FRSA) has adjusted user rates for residential, industrial and commercial customers. The annual rate increase reflects the need for FRSA to meet Illinois Environmental Protection Agency (IEPA) mandates, which require that FRSA meet strict guidelines in eliminating phosphorus from wastewater; and the increasing costs in both the maintenance of an aging infrastructure and required capital improvement projects. For additional information, read the attached press release.