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Sewer Service Charges and Ordinances

Revenues to operate the District are collected yearly from residents and businesses that are connected to the sanitary sewer system. The following information will explain how yearly Sewer Service Charges are calculated and what steps businesses can take to minimize the charges.

Annual Sewer Service Charges are placed on your Alameda County property tax statement. The charges appear on the tax statement as a line item next to our phone number 477-7500 and are listed as "Union Sewer Svc." Sewer Service Charges are not a property tax and are not related to the assessed value of a property. They represent a charge for a service provided, similar to your phone and P.G. & E. bills. We simply include the yearly charges on the property tax statement to save the administrative cost of generating and mailing our own invoices. More details on how the charges are calculated are provided below.

Residential Customers are charged at a flat rate.

Charges for residential customers are based on a flat rate per dwelling unit. The current rate (2014-2015) per dwelling unit is $357.02 per year. This is the charge for a single family home. A property with multiple housing units such as an apartment complex is charged $315.25 for each dwelling unit on the property. For example, a ten unit apartment complex would be charged $315.25 x 10 or $3,152.50 per year. This rate is effective July 15, 2014.

How water use is determined for Commercial & Industrial Charges

Charges for commercial and industrial customers are based on the volume and pollutant strength of the wastewater being treated. The volume of wastewater is determined from water meter records obtained from the Alameda County Water District. Credit is given for water used that is not discharged to the sanitary sewer, such as landscape irrigation. Due to the lead time involved to get yearly charges placed on the County property tax statements, the Sewer Service Charges on the current year's tax statement reflect services already provided. Water use for purposes of computing the service charge is measured from March through February of the previous year. The Sewer Service Charge for this period is then placed on the property tax statement that is mailed out in October, with the first installment due December 10th. The Sewer Service Charge Timing Chart below, illustrates when charges are collected.


Timeline for Commercial & Industrial Users

How pollutant strength is determined for Commercial and Industrial Charges

Pollutant strength is measured in samples of wastewater for two components: chemical oxygen demand (COD), and suspended solids (SS). Wastewater with high strength costs the District more to treat. For example, wastewater with high levels of suspended solids produces more sludge (a by-product of treatment). Sludge is treated and then disposed of at an agricultural site. If more sludge is produced, our hauling and disposal costs are higher. Therefore, rates are structured so that customers are charged based on the volume of solids they contribute to the system.

Wastewater strength for commercial and industrial customers is determined by one of three primary methods: General Assignment, Specific Assignment, and Direct Sampling.

General Assignment
: Most commercial and industrial customers, or properties that include several different types of businesses, are calculated by the General Assignment method. With this method, customers are assigned a general strength of strong, moderate or weak. The three rate components, VOLUME, COD, and SS are combined into one rate per 1,000 gallons of wastewater discharged. The current rates for Fiscal Year 2014 (as of July 15, 2013) are shown below:

  • Strong $7.47 per 1,000 gallons per year

  • Moderate $4.03 per 1,000 gallons per year

  • Weak $3.53 per 1,000 gallons per year

Specific Assignment: Strength values are based on studies of wastewater from similar types of businesses and represent an "average" for that group. The total charges under this method are the sum of three components - volume, COD, and SS. USD's current rates for restaurants are listed below:

  • Fast Food Restaurants $7.14 per 1,000 gallons per year

  • Full Service Restaurants $9.13 per 1,000 gallons per year

Direct Sampling: This method applies only to industrial customers with industrial discharge permits. Under this method, samples of wastewater are collected and sent to a laboratory for analysis. Both COD and SS are measured and then averaged with other samples taken that year to determine an average strength for use in calculating Sewer Service Charges. The sum of three components determines the total charge. The current rates for each component are:

  • Volume (Flow) = $2.25 per 1,000 gallons per year

  • COD = $227.54 per 1,000 pounds per year

  • SS = $417.17 per 1,000 pounds per year

For more details on how annual charges are calculated, see the sample rate calculations for all three methods.

Sample Rate Calculations

How Sewer Service Rates Are Established

Union Sanitary District is governed by a five-member Board of Directors which is elected by the residents of the service area. Rates are reviewed each year based on financial plans for the District and are subject to approval by the Board. Before rates are set, a notice is published in the Argus newspaper. If a rate increase is proposed, the District also complies with Proposition 218 "Right to vote on Taxes" notification requirements. The annual public hearing is normally scheduled in June of each year with rates becoming effective in July. Customers are encouraged to participate in the public hearings and can send written comments on items before the Board to the attention of the General Manager.

How Sewer Service Charges Can Be Minimized

For commercial and industrial customers that are under the Specific or General Assignment methods, the most effective way of minimizing charges is water conservation. Charges are directly tied to the volume of water used; therefore, saving-water will reduce the Sewer Service Charge as well as charges for water. There is a wide variety of water-saving fixtures on the market. Low-flow toilets, shower heads and faucet aerators are among the most cost effective. For industrial customers under the Direct Sampling method, water conservation and any reductions in pollutant loadings will minimize service charges. One of the most effective ways to reduce loadings is to minimize the amount of waste being discharged to the sanitary sewer system. The District sponsors a Pollution Prevention Program to assist customers in reducing their waste streams. Call in the District's Commercial/Residential Customer Team at (510) 477-7500 for more information. More specific information on water conservation can be obtained from the Alameda County Water District at (510) 659-1970.

Renting or Leasing

Due to the lag in billing, commercial or industrial customers who rent or lease their property should carefully consider how Sewer Service Charges are addressed in the lease or rental agreement. Changes in tenants with different demands for water or that have different wastewater strengths will affect the yearly service charge. A landlord may not become aware of potential changes in service charges until well after tenant changes have occurred. All Sewer Service Charges are billed to the property owner. Property owners are responsible for paying the charges whether or not they are able to collect from their tenants.


Sewer Service Charge Ordinance Ordinance 31.37 An ordinance providing for the establishment of sewer service charges for fiscal years 2014, 2015 and 2016.  Effective date July 15, 2014.