What Is a Sewer Bill vs a Water Bill?

Household utility bills often include charges for essential services like water and sewer, which are distinct yet frequently appear together on a single statement. While both relate to water use, they cover different aspects of the water cycle within a property. This article will clarify the nature of water and sewer bills and explain how their charges are typically determined and presented.

What is a Water Bill?

A water bill reflects the cost of providing clean, potable water directly to a property. This service ensures water is available for drinking, cooking, cleaning, and other indoor and outdoor uses. Utility companies measure water consumption using meters, typically in units such as gallons or centum cubic feet (CCF). One CCF is equivalent to 748 gallons of water.

The charges on a water bill cover expenses for sourcing raw water from rivers, lakes, or aquifers, and for water treatment to meet safety standards. The bill also contributes to the maintenance and expansion of infrastructure, such as pipes, pumps, and storage tanks, necessary to distribute water throughout a service area. It also accounts for the energy needed to move and deliver water, as well as personnel costs for daily operations.

What is a Sewer Bill?

A sewer bill, also known as a wastewater bill, represents the cost of collecting, treating, and disposing of wastewater from a property. This wastewater originates from sources like sinks, toilets, showers, and washing machines, and is transported through a network of sewer pipes. The bill supports the operation and maintenance of the collection system, including pipes, manholes, and lift stations, which move wastewater to treatment plants.

Sewer charges are often connected to water consumption because most water supplied to a property eventually enters the sewer system as wastewater. Utility providers do not have separate meters for outgoing wastewater, so they estimate sewer usage based on metered incoming water usage. Funds collected through sewer bills are used for wastewater treatment, which removes pollutants before the cleaned water is returned to the environment.

How Water and Sewer Charges are Determined

Utility companies use several methods to calculate water and sewer charges, often combining fixed charges and volumetric rates. Fixed charges, sometimes called base rates or customer fees, are a consistent amount billed monthly or quarterly, regardless of water used. These fees help cover the utility’s overhead, customer service, and infrastructure maintenance, ensuring the system’s readiness to serve.

Volumetric rates, or usage charges, are based on the quantity of water consumed, measured by the water meter. This per-unit charge reflects the costs of producing and treating water, including chemicals and energy. Many utilities employ tiered pricing, where the cost per unit of water increases as consumption rises beyond certain thresholds. For example, the first few thousand gallons might be billed at a lower rate, with subsequent blocks of usage charged at progressively higher rates.

Sewer charges are determined by metered water consumption, as wastewater is not directly metered. Some utilities use a percentage of water usage (e.g., 90-95%) to estimate wastewater volume, acknowledging that some water, like outdoor irrigation, does not return to the sewer system. To account for outdoor water use, some utilities offer adjustments or caps on sewer charges. This can involve using a winter average of water consumption as the basis for sewer billing, or allowing for separate irrigation meters to exclude outdoor water from sewer calculations.

Interpreting Your Combined Utility Statement

A typical utility statement combines both water and sewer charges into a single bill. Understanding the different sections and line items on this statement helps in tracking usage and costs. The bill usually provides a summary of charges, clearly separating the amounts for water service and sewer service.

Information to locate includes meter readings and billing period dates. The statement also shows the unit of measurement used, such as gallons or CCF, and the rate applied per unit of consumption for both services. Fixed charges, often labeled as a “base charge” or “customer charge,” appear as a flat fee independent of usage. Some bills may include additional fees or surcharges for regulatory compliance, infrastructure improvements, or stormwater management. Many utilities provide a breakdown of charges in a “billing detail” or “summary of charges” section, and some offer historical usage graphs to help consumers monitor their consumption patterns.