(a) Authority.Pursuant to the provision of Public Law 92-500, section 240(b), the town, having received a federal grant for the construction of treatment works, shall adopt a system of charges to ensure that each person (or user) receiving waste treatment services within the town’s jurisdiction will pay a proportionate share of the costs of operation and maintenance (including replacement) of any waste treatment services provided by the town.

(b) Intent.The intent of the user charges is to distribute the cost of operation and maintenance of publicly owned treatment works to the pollutant source and to promote self-sufficiency of treatment works with respect to operation and maintenance costs.

(c) Definition.The term "replacement" referred to in subsection (a) of this section is defined as those expenditures for obtaining and installing equipment, accessories, or appurtenances necessary during the service life of the treatment works to maintain the capacity and performance for which such works are designed and constructed. The term "operation and maintenance" includes replacement.

(d) User class.Each user shall be charged a share of the treatment works operation and maintenance cost based on the measured proportionate contribution to the treatment works loading. Generally, the user charge will be dependent upon flow insofar as BOD, suspended solids, nitrogen and other pollutant contributions discharged by all users are approximately equal. Where such pollutants exceed the range of concentration of these pollutants in normal domestic sewage, a surcharge will be added to the base charge. The models used in calculating the user charge are defined in subsection (f) below.

(e) User charge criteria.The user charge system shall be approved by the regional administrator of the Environmental Protection Agency and shall be maintained by the town in accordance with the following requirements.

1. The user charge system must result in the distribution of the cost of operation and maintenance of treatment works within the town’s jurisdiction to each user (or user class) in proportion to such user’s contribution to the total wastewater loading of the treatment works. Factors such as strength, volume and delivery flow rate characteristics shall be considered and included as the basis for the user’s contribution to ensure a proportionate distribution of operation and maintenance costs to each user (or user class).
2. The user charge system must generate sufficient revenue to offset the cost of all treatment works operation and maintenance provided by the town.

(f) Model user charge systems.The user charge system adopted by the town shall result in the distribution of treatment works operation and maintenance costs to each user (or user class) in approximate proportion of the contribution to the total wastewater loading of the treatment works. The following user charge models shall be used for this purpose. The symbols used in the models are as defined below:

• Cf= Total fixed operation and maintenance (O&M) cost per unit of time. Ct= Total O&M cost per unit of time. Cu= A user’s charge for O&M per unit of time. Cs= A surcharge for wastewaters of excessive strength. Vu= Volume contribution from a user per unit of time. Vt= Total volume contribution from all users per unit of time. Bc= O&M cost for treatment of a unit of biochemical oxygen demand (BOD). B = Concentration of BOD from a user above a base level. Sc= O&M cost for treatment of a unit of suspended solids (SS). S = Concentration of SS from a user above a base level. Nc= O&M cost for treatment of a unit of ammonia (NH3-N). N = Concentration of NH3-N from a user above a base level. Pc= O&M cost for treatment of a unit of any pollutant. P = Concentration of any pollutant from a user above a base level. 
  1. Model no. 1.Whereas the treatment works is primarily flow dependent as the BOD, suspended solids, and other pollutant concentrations discharged by the majority of users are approximately equal, the user charge is therefore developed on a volume basis in accordance with the model below: 
     • Cu= Ct____ Vt(Vu) = Cf____ number of sewer customers
  2. Model no. 2.When determined by the town that BOD exceeds the range of concentration of these pollutants in normal domestic sewage, a surcharge added to a base charge, calculated by means of model no. 1, shall be levied. The surcharge shall be computed by the model below: 
     • Cs= Bc(B) + Sc(S) + Nc(N) + Pc(P) Vu
     • Refer to section 36-158 for the established baseline pollutant concentrations.

(g) Basis of charges.User charges may be established based on a percentage of the charge for water usage. However, the unit rate sewer use charge for the largest volume users must be as great or greater than the unit cost of operation and maintenance (excluding debt service). In such event, a surcharge shall still be levied in accordance with the provisions of model no. 2 in subsection (f)(2) above. The system of user charges for the town shall be based on total system costs, including operation and maintenance expenses and debt service. The debt service portion of the annual system expense will be allocated on a unit rate basis with no discount to the large volume users.

(h) Charges for unattributable flow.Charges for flow to the town’s treatment plant not directly attributable to the users shall be distributed among all users of the treatment plant based upon the total volume of flow of the users.
(Ord. of 4-5-93, § X(1))