• Minimum Base Charge and Sewer Rate Tables

    Minimum Base Charge (Service Fee)

    The minimum base charge is a service fee that applies to all residential, commercial, and industrial sewer customers based on the size of the property's water meter. The minimum base charge includes the first 3 CCF1 of water used each month, based on 30 days of service. If there are greater or less than 30 days of service, the amount is prorated.

    See the minimum base charge chart below:

    Minimum Base Charges for Residential, Commercial, and Industrial Customers
    Meter Size (Inches)
    Monthly Bills ($)
    Monthly Bills - 25% CAP Discount ($)
    1 1/2

    Commodity Charge Rates

    The commodity charge is applied to all residential, commercial, and industrial customers who use more than 3 CCF of water each month. The commodity charge is calculated by multiplying the cubic feet of water used (beyond the monthly allowance of 3 CCF) by the established sewer rate. Learn about the winter period2for residential customers.

    See the commodity charge charts below:

    Commodity Charges for Residential, Commercial, and Industrial Customers 3
    Monthly Water Usage
    Sewer Rate ($)
    Sewer Rate - 25% CAP Discount ($)
    Up to 3 CCF
    Included in the minimum base charge
    Included in the discounted minimum base charge
    Greater than 3 CCF, up to 50 CCF
    $5.879 per CCF
    $4.409 per CCF
    More than 50 CCF
    $4.701 per CCF
    $3.526 per CCF

    Industrial Customer Rates and Charges

    Industrial customers may be charged additional fees to cover costs associated with their discharges, including:

    • Surcharge rates
    • Industrial pretreatment charges
    Surcharge Rates

    For customers having high strength waste discharge, the surcharge is computed on the following basis:

    Surcharge Rates
    Suspended Solids (SS)
    $0.002756 per CCF for each mg/l of SS strength above 300 mg/l
    Biochemical Oxygen Demand (BOD)
    $0.004707 per CCF for each mg/l of BOD strength above 240 mg/l
    Nitrogenous Oxygen Demand (NOD)
    $0.004122 per CCF for each mg/l of Total Kjeldahl Nitrogen (TKN) strength above 25 mg/l

    Provided, however, that to the extent the strength of a pollutant is less than eighty percent (80%) of the corresponding value for normal strength sewage, a credit shall be allowed as an offset against surcharge otherwise due. The credit shall be calculated by multiplying the herein above specified surcharge rate for the pollutant in question times the difference between actual pollutant concentration in mg/l and eighty percent (80%) of the corresponding value for normal sewage. No credit shall be allowed in excess of surcharge otherwise due.

    Industrial Pretreatment Charges

    All users required to apply for and obtain a wastewater discharge permit or which are subject to federal pretreatment standards, as specified in the MSD Rules and Regulations, shall be subject to the payment of a pretreatment charge(s), as determined by the Director. Said pretreatment charge(s) shall be sufficient to recover, in whole or in part, the costs for the MSD Pretreatment Program including investigations, record keeping, administration, and monitoring of industrial waste charges to the system. Each industrial user shall pay a pretreament charge(s) as follows:

    Industrial Pretreatment Charges
    Annual Fee

    $2,889 per annum

    Monitoring Charge
    $17,912 maximum per monitoring event

    Notes & Definitions

    1CCF (centum cubic feet)

    1 CCF = 100 cubic feet or 748 gallons

    2Winter Period for Residential Customers (Single and Two-Family Homes)

    In the months of January, February, and March, the commodity charge for residential customers is based on the actual amount of water used. In the months of April through December, the commodity charge is based on whichever is less: (a) the actual amount of water used in that month or (b) the average amount of water usage from the months of January, February, and March. This average is known as the "winter period." Many residential customers (single and two-family homes) use greater amounts of water during the warm, summer months (e.g., watering lawns, gardening), much of which never enters the sewer system. Since sewer bills are based on water usage, MSD uses a customer’s average water consumption during January, February, and March of each year as the maximum water usage to calculate the monthly commodity charge for the next 9 months (April-December). See the example below for how to calculate the maximum water usage. If a customer uses less water during the billing period than the maximum set during the winter period, the account is charged for the lower usage figure. If a customer uses more water during a billing period than the maximum set during the winter period, the account is only charged for the maximum set during the winter period.

    New accounts without a history of winter period consumption are billed at a maximum default of 8 CCF for single-family homes and 12 CCF for two-family homes. A new winter period maximum water consumption rate is established each year during the winter period.

    Example of How to Calculate Maximum Water Usage During the Winter Period
    Example Consumption
    Days of Service (DOS)
    January: 8 CCF
    28 DOS
    February: 6 CCF
    30 DOS
    March: 7 CCF
    31 DOS
    TOTALS: 21 CCF
    89 DOS

    Calculation: 21 CCF / 89 DOS x 30 DOS = 7.078 CCF (maximum water usage) for the next 9 months (April - December).

    Note: Commercial customers do not have a "winter period."
    Commercial customers are charged based on the water used during a billing period that is subject to a sewerage charge. MSD will consider application, fully supported, for adjustment due to non-sewered water use. All well water and water reaching the system from other sources will be considered in the base charge.

    3OM&R Portion

    A portion of the minimum base charge and the sewer rate (used to calculate the commodity charge) is specifically allocated to operation, maintenance, and replacement (OM&R) costs for sewer-related infrastructure. Public Law 95-217 requires public notice of the "OM&R" portion" of each cost. By definition, replacements are those necessary to extend the life of facilities and not the total replacements of the entire system. Please note: The OM&R portion does not impact MSD's Customer Assistance Program (CAP). For detailed information on OM&R costs, please view the most current Rate Schedule Flyer under Downloads.