(A) (1) Users of the city wastewater treatment works shall be identified as belonging to one of the following user classes:
(a) Residential;
(b) Nonresidential; or
(c) Industrial.
(2) The allocation of users to these categories for the purpose of assessing user charges and debt service charges shall be the responsibility of the City Administrator-Clerk-Treasurer. Allocation of users to user classes shall be based on the substantive intent of the definitions of these classes contained herein.
(B) Each user shall pay operation, maintenance and replacement costs in proportion to the user’s proportionate contribution of wastewater flows and loadings to the treatment plant, with the minimum rate for loadings of BOD and TSS being the rate established for concentrations of 225 mg/l BOD and 250 mg/l TSS (Normal Domestic Strength Wastewater). Those industrial users discharging segregated normal domestic strength wastewater only can be classified as nonresidential users for the purpose of rate determination.
(C) The charges assessed residential users and those users of other classes discharging normal domestic strength wastewater shall be established proportionately according to billable wastewater volume. Billable wastewater volume shall be calculated as follows:
(1) Residential users.
(a) Billable wastewater volume for residential users shall be calculated on the basis of metered water usage. The per quarter billable wastewater volume shall be equal to quarterly metered water usage as average between the first and last quarters of the calendar year.
(b) The city may require residential users to install water meters for the purpose of determining billable wastewater volume.
(2) Nonresidential users.
(a) The billable wastewater volume of nonresidential users may be determined in the same manner as for residential users, except that if the city determines that there are significant seasonal variations in the metered water usage of nonresidential users resulting in a proportionate increase in wastewater volume, then billable wastewater volume shall be:
1. Calculated on the basis of quarterly metered water usage as recorded throughout the year; and
2. Calculated on the basis of wastewater flow meters.
(b) The city may, at its discretion, require nonresidential users to install such additional water meters or wastewater flow meters as may be necessary to determine billable wastewater volume.
(D) User charges for normal domestic users shall be determined as follows:
(1) Calculation of unit cost for treatment of normal domestic strength wastewater.
Uomr = Comr
Tbwv
Tbwv
Where: Uomr = Unit cost for operation, maintenance and replacement
Comr = Total annual OM & R costs
Tbwv = Total annual billable wastewater volume in kgal.
(2) Calculation of user charge.
Uc = Uomr x bwv
Where: Uc = User charge
Uomr = Unit cost for operation, maintenance and replacement in $/kgal.
bwv = Billable wastewater volume of a particular user in kgal.
(E) Local construction costs of the wastewater treatment facility will be recovered through a debt service charge calculated using usage, connection and assessment charges as follows:
(1) Calculation of debt service unit cost for wastewater volume.
Uds = Cds
Tbwv
Tbwv
Where: Uds = Unit cost for debt service in $/kgal.
*Cds = Cost of annual debt service assigned for wastewater volume.
Tbwv = Total annual billable wastewater volume in kgal.
*City may reduce the cost of annual debt service through the use of other city funds at its discretion.
(2) Calculation of debt service billable connection cost.
UD = CDC
TC
TC
Where: UD = Unit billable connection cost for debt service
*CDC = Costs of annual debt service assigned for connections
Tc = Total number of billable connections
*City may reduce the cost of annual debt service through the use of other city funds at its discretion.
(3) Assessment. Calculation of debt service for assessment of construction costs for the wastewater treatment facility will be recovered through an assessment as established by the City Council.
(4) Calculation of debt service charge.
Dc = Uds x bwv + UD x U + Assessment
Where: Dc = Debt service charge
Uds = Unit cost for debt service in $/kgal
UD = Unit billable connection cost for debt service
U = Number of billable connections for particular user
bwv = Billable wastewater volume of a particular user in kgal
Assessment = Amount of assessment charged per year
(F) Determination of sewer service charges. The sewer service charge for a particular connection shall be determined as follows:
SSC = Uc + Dc
Where: SSC = Sewer service charge
Uc = User charge
Dc = Debt service charge
(G) Additional assessments. The sewer service charges established in this subchapter shall not prevent the assessment of additional charges to users who discharge wastes with concentrations greater than normal domestic strength or wastes of unusual character or contractual agreements with such users as long as the following conditions are met:
(1) The user pays operation, maintenance and replacements costs in proportion to the user’s proportionate contribution of wastewater flows and loadings to the treatment plant, and no user is charged at a rate less than that of normal domestic strength wastewater;
(2) The measurements of such wastes are conducted according to the latest edition of Standard Methods for the Examination of Water and Wastewater in a manner acceptable to the city as provided for in this chapter. A study of unit costs of collection and treatment processes attributable to flow, BOD, TSS and other significant loadings shall be developed for determining the proportionate allocation of costs to flows and loadings for users discharging wastes of greater than normal domestic strength or wastes of unusual character.
(Ord. 117½, passed 2-26-86)