(a) 
A user classification is hereby established for all users of the municipal wastewater facilities as follows:
(1) 
User classification Class A: Residential users.
(2) 
Class B: Commercial users.
(b) 
Class A users shall include all residential-type users, including but not limited to residences, apartment units, trailer court units, duplexes or any other primarily intended for domestic or residential-type use. The city may include small office buildings, churches and other low-volume (similar to domestic volume) users in Class A.
(c) 
Class B users shall include commercial users, such as, but not limited to, restaurants, cafes, carwashes, schools, hospitals, nursing homes, offices, hotels, motels, laundries, grocery stores, department stores, etc., not included in Class A.
(1975 Code, sec. 31-101; 2004 Code, sec. 13.601)
All users of the municipal wastewater facilities shall be charged on the basis of the volume discharged to the sanitary sewer and the strength of the wastewater discharged. The strength of the wastewater will be measured by the biochemical oxygen demand (BOD) and the total suspended solids (TSS) content. The normal domestic wastewater strength for the city has been established not to exceed 200 mg/l BOD5 and 200 mg/l TSS, and it has been determined that wastewater strengths for Class A and Class B users are approximately equal. Therefore, all users of the municipal wastewater facilities shall be charged on a volume basis, inclusive of the normal domestic wastewater strength. Those users discharging wastewater that is measured to contain BOD5 and TSS concentrations in excess of the normal domestic waste strength shall pay an additional surcharge based on the excess. The charges for volume and extra-strength surcharge shall be determined as follows in this section.
(1) 
Volume charges.
The charges shall be determined in accordance with the following formula:
Cu = Cb + (Ct/Vt)Vu
Symbols and definitions:
Cu = A user’s charge per unit of time.
Cb = A user’s base minimum charge per unit of time for costs not associated with operations and maintenance of flow related units of wastewater facilities.
Ct = Total operation, maintenance and replacement (OM&R) costs per unit of time of flow related units of wastewater facilities.
Vt = Total volume contribution from all users per unit of time (may include extraneous flows).
Vu = Volume contribution from a user per unit of time.
(A) 
Determination of Vu. The volume charges per month to be billed to Class A users shall be equal to the average monthly water consumption metered during a three-month base period during December, January and February each year. This procedure will be utilized in order not to account for any water used during warmer weather months for purposes such as lawn and garden watering or other uses which will result in the water not being returned to the sanitary sewer. The water consumption per month to be billed for Class B users shall be the actual water consumption recorded each month for the purpose of computation of the water bill. The intent of this article is to bill the sanitary sewer users based on their volume contribution to the system. In the event that individual users have cause to believe that the water was metered is substantially greater than their sanitary sewer contribution, they shall prepare a written description of the water use facilities and disposition for submittal to the city manager. The city manager shall review the written description and, if necessary, conduct such field investigations as required to verify the claim. Following verification, the city manager shall adjust the billing as required to reflect wastewater contribution. Vu will be expressed as the number of 1,000-gallon units of water consumed by the user.
(B) 
Calculation of Cb. Cb is the user’s share of monthly costs not related to operations, maintenance and replacement of the wastewater collection system, lift stations and treatment plant. These costs, accountable to customer service, will reflect the actual expenditures required by the wastewater system, including, but not limited to, city administration, billing, account collection and ordinance enforcement. Customer service costs include:
(i) 
Salaries and wages:
a. 
Full-time.
b. 
Part-time.
c. 
Per diem.
(ii) 
Indirect salary and wage costs:
a. 
FICA.
b. 
Health insurance.
c. 
Retirement.
d. 
Workmen’s compensation.
e. 
Unemployment insurance.
f. 
Other (vacations, sick leave, etc.).
(iii) 
Contractual services:
a. 
Legal.
b. 
Financial (audit).
c. 
Insurance.
d. 
Printing.
e. 
Other.
(iv) 
Materials and supplies:
a. 
Motor vehicle fuel and lubricants.
b. 
Equipment under $100.00.
c. 
Office supplies.
d. 
Cleaning supplies.
e. 
Other.
(v) 
Utilities:
a. 
Power-electrical and fuel requirements for buildings and administrative offices.
b. 
Telephone.
c. 
Gas.
d. 
Water.
e. 
Other.
(vi) 
Equipment replacement.
a. 
Motor vehicles.
b. 
Office equipment.
c. 
Other.
Following the determination of the total customer service cost, Cb is calculated by dividing the total cost by the total number of sanitary sewer connections.
(C) 
Calculation of Ct. Ct is the total cost of operation, maintenance and replacement of flow related units of the wastewater facilities, such as the collection system, lift stations and treatment facilities. Operation, maintenance and replacement costs include the following:
(i) 
Salaries and wages:
a. 
Full-time.
b. 
Part-time.
c. 
Per diem.
(ii) 
Indirect salary and wage costs:
a. 
FICA.
b. 
Health insurance.
c. 
Retirement.
d. 
Workmen’s compensation.
e. 
Unemployment insurance.
f. 
Other (vacations, sick leave, etc.).
(iii) 
Contractual services:
a. 
Engineering.
b. 
Insurance.
c. 
Operator training.
d. 
Debt service.
e. 
Other.
(iv) 
Materials and supplies:
a. 
Chemicals - disinfection.
b. 
Chemicals - other.
c. 
Motor vehicle fuel and lubricants.
d. 
Laboratory supplies.
e. 
Tools under $100.00.
f. 
Office supplies.
g. 
Cleaning supplies.
h. 
Other.
(v) 
Utilities:
a. 
Power - electrical and fuel requirements for treatment works processing and plumbing.
b. 
Telephone.
c. 
Gas.
d. 
Water.
e. 
Other.
(vi) 
Equipment replacement:
a. 
Tools over $100.00.
b. 
Laboratory equipment.
c. 
Motor vehicles.
d. 
Mowing equipment.
e. 
Office equipment.
f. 
Pumps.
g. 
Motors.
h. 
Other.
(vii) 
Miscellaneous costs: State and federal inspection fees.
(D) 
Calculation of Vt. Vt is the total volume of wastewater, including extraneous flows, received by the wastewater treatment plant during the year ending on the 31st day of December prior to the rate calculation period. Vt shall be expressed in the number of 1,000-gallon units of flow.
(E) 
Calculation of Ct/Vt shall be calculated by dividing the total cost of operation, maintenance and replacement (Ct) by the total wastewater flow (Vt) expressed in 1,000-gallon units. This determination shall be expressed in cost of OM&R per 1,000 gallons of sewage flow.
(2) 
Excessive-strength charge.
For any user, when the BOD exceeds two hundred (200) mg/l or the suspended solids exceed two hundred (200) mg/l, a surcharge shall be added to the basic charge. This surcharge shall be calculated by the following formula:
Cs = Bc(B) + Sc(S)
Symbols and definitions:
Cs = A monthly surcharge for wastewaters of excessive strength
Bc = O&M cost for treatment of a unit of biochemical oxygen demand (BOD) B = Quantity of BOD from a user above the base level of 200 mg/l
Sc = O&M cost for treatment of a unit of suspended solids (SS)
S = Quantity of TSS from a user above the base level of 200 mg/l
(A) 
Calculation of Bc and Sc. A unit of BOD5 or TSS shall be defined as that parameter expressed as pounds. Since the base level of BOD5 or TSS has been defined as 200 mg/l, the total number of BOD5 or TSS units (lbs.) treated can be calculated as follows:
(i) 
Total annual sewage flow (million gallons) x 8.34 x 200 = lbs./yr.
(ii) 
Total annual sewage flow will be the total for a year ending on the 31st day of December prior to the rate calculation period.
The OM&R cost per pound of BOD5 or TSS can be calculated by dividing the total annual cost of OM&R (from subsection (1)(C) above) by the total lbs. of BOD5 or TSS per year as calculated above. These determinations shall be expressed as the cost/lbs. of unit (Bc or Sc).
(B) 
Calculation of B and S.
B and S is the quantity of BOD5 and TSS, respectively, from a user above the base level of 200 mg/l. User monitoring to determine B and S shall be done by the city in all sewer connections that, due to operational type or category, would be normally expected to contribute wastewater containing greater than the base sewage strength. Monitoring to determine surcharges shall be done at a minimum annually and shall consist of a composite sample or samples reflecting the 24-hour use characteristics of the entity monitored. All wastewater analysis will be conducted in laboratory facilities approved by the city and by methods approved in the latest revision of Standard Methods for the Examination of Water and Waste.
(i) 
The quantity of BOD5 and/or TSS from a user above the base level will be calculated as follows:
B = Actual BOD5 (mg/l) - 200 mg/l x 8.34 x users monthly flow in MG
S = Actual TSS (mg/l) - 200 mg/l x 8.34 x users flow in MG
(ii) 
These determinations shall be expressed as the lbs. of BOD5 (B) or lbs. of TSS (S) discharged above the base strength.
(iii) 
Since the excess BOD5 or TSS for billing purposes will be determined annually, a factor for each parameter can be calculated annually to be multiplied by the user’s monthly flow expressed in millions of gallons:
Annual BOD5 factor = (actual BOD5 - 200) x 8.34 x Bc
Annual TSS factor = (actual TSS - 200) x 8.34 x Sc
(iv) 
Then the monthly billing for extra strength surcharge is calculated as follows:
(Annual BOD5 factor x flow in MG) + (Annual TSS factor x flow in MG).
(1975 Code, sec. 31-102; 2004 Code, sec. 13.602)
This article shall be reviewed annually regarding the wastewater contribution of users and user classes, the methods to determine the costs of operation, maintenance and replacement of the treatment works collection system and lift stations, base sewage strength and its approved user charge system. The charges for users or user classes shall be reviewed to accomplish the following:
(1) 
To maintain the proportionate distribution of operation and maintenance costs among users and user classes based on wastewater contribution.
(2) 
To generate sufficient revenue to pay the total operation and maintenance cost necessary to the proper operation and maintenance (including replacement) of the treatment works.
(1975 Code, sec. 31-103; 2004 Code, sec. 13.603)
(a) 
On an annual basis effective October 1 of each year, the city council shall adopt a user charge rate ordinance that establishes the monthly customer service rate charge billed to each customer, the cost of operation, maintenance and replacement of facilities per one thousand (1,000) gallons of actual water consumption (or base period average consumption for Class A users) and the cost of treatment per unit (pound) of BOD5 and TSS.
(b) 
Operational data, such as wastewater flows and sewage strength, utilized in the calculations shall be for the year ending December 31 prior to the rate calculation. Class A water consumption utilized in the billing shall be for the base period during the previous December, January and February prior to the rate calculations. The total annual customer service costs and the annual cost of operation, maintenance and replacement of facilities shall be as budgeted for the fiscal year beginning October 1 each year based on budget items as specifically identified in this article.
(1975 Code, sec. 31-104; 2004 Code, sec. 13.604)
The city shall utilize the various means available, including, but not limited to, the news media, utility bill inserts and public meetings, to inform system users of proposed rate calculations and the base period in which Class A user volumes will be determined.
(1975 Code, sec. 31-105; 2004 Code, sec. 13.605)
The costs of operation, maintenance and replacement for all flows not directly attributable to users (such as infiltration/inflow) shall be distributed among users on the same basis as operation and maintenance charges.
(1975 Code, sec. 31-106; 2004 Code, sec. 13.606)
A recordkeeping system shall be established and maintained by the city to document calculations used to initiate and determine the user charge rates.
(1975 Code, sec. 31-107; 2004 Code, sec. 13.607)
The user charge system shall take precedence over any terms or conditions of agreements or contracts which are inconsistent with applicable portions of this article, between the city and any of the users.
(1975 Code, sec. 31-108; 2004 Code, sec. 13.608)