The District is implementing a fixed rate billing structure that will replace the annual consumptive-based billing approach currently used for business customers only in the City of Ridgefield. Customers will be billed at the current District monthly rates using a base charge that represents the sewer demand and use for the business. The base charge is expressed in a unit of flow called an Equivalent Residential Unit (ERU), which equates to 200 gallons per day. The base charge is determined considering a business’s service characteristics and historic and estimated demand.