Illinois Plumbing Code Practice

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Prepare for the Illinois Plumbing Code Test! Enhance your skills with diverse multiple-choice questions and detailed explanations. Ace your plumbing exam with ease!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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What should be the maximum chlorine residual in water samples from a potable water system for a reliable laboratory result?

2 parts per million
4 parts per million
6 parts per million
8 parts per million

The correct answer is: 4 parts per million

The maximum chlorine residual in water samples from a potable water system for reliable laboratory results is set at 4 parts per million. This level is crucial because it balances the need for effective disinfection while minimizing interference with laboratory analyses. Higher chlorine levels can lead to issues such as the degradation of certain compounds or the production of chlorinated byproducts, which may skew the results or hinder the detection of specific contaminants. Maintaining the chlorine residual at or below 4 parts per million helps ensure that tests provide accurate readings of the water's microbiological and chemical quality, supporting both public health standards and regulatory compliance.