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to adopt effluent limits for its industrial dischargers that eliminated the 
spector of discrimination could arise if limits are based on a discharger's 
size. Other advantages to the East Bay sampling program are discussed in the 
section below on developing pretreatment rate structures. 
Although much of the sampling work carried out for this pretreatment program 
was conducted by the POTW staff, East Bay also developed a questionnaire 
that large customers could use in characterizing their own wastes. Such a 
questionnaire program could be a useful addition to any local pretreatment 
effort in two ways. First, the questionnaire has enormous educational value 
for the industrial customer. In areas where no previous source control or 
enforcement program was in effect, industries subject to pretreatment generally 
know very little about their wastewater. Going through the process of answer- 
ing such a questionnaire enables dischargers to discover the exact nature of 
their effluents, as well as to directly experience the types of problems and 
difficulties that are encountered by a POTW when it obtains a representative 
sample of industrial wastewater. Industrial customers agreeing to complete 
a questionnaire are generally easier to talk to about the need for controls, 
Since they can better understand the potential impact of an uncontrolled dis- 
charge on both a POTW and its receiving waters. 
A second benefit of carrying through the questionnaire program relates to 
fair allocation of the overall costs of sampling. East Bay pretreatment pro- 
gram directors felt that part of the total cost of a sampling program should be 
borne by the customers regulated. They reasoned that it was fair for larger 
customers to determine the most satisfactory and economical methods of sampling 
and testing their own wastes. Such an approach is completely within the 
general philosophy of pollution control legislation that users pay the costs 
of their pollution-causing activities. How did industrial customers respond? 
The questionnaire was sent to approximately 150 of the largest East Bay users; 
although answering the questionnaire was not legally required, approximately 90 
industries returned completed forms to the District. 
Setting Equitable Pretreatment Charges 
Since the development of a pretreatment program coincided with East Bay's move 
to secondary treatment, an analysis of the District's capital and operating 
expenses to determine the costs of treatment for different parameters for waste- 
water strength was undertaken at the same time. The general revenue system 
used by the District draws from tax collection and service charges. Pretreat- 
ment bills are calculated on the basis of a unit rate calculated for each 
parameter, multiplied by the number of units discharged, as indicated in an 
industrial user's pretreatment program permit. 
A short description of the rationale behind East Bay's general revenue pro- 
gram is in order here. The service charges provide the District with the money 
needed to offset the capital costs of existing facilities and the ongoing opera- 
tion and maintenance costs that can be directly attributed to users to the 
sewer system. Approximately 50 percent of the total capital expenses and 96 
percent of the 0&M costs are paid for through the service charge collected. Ad 
valorem taxes are used to pay for those capital costs that can be attributed to 
