Rhode Island Journeyman Plumber Practice Exam

What method is used for disinfection of a potable water system?

1. Chlorination only

2. Flushing

3. Air gap or air gap device

4. UV treatment

The correct answer is: Air gap or air gap device

The correct method for disinfection of a potable water system involves using an air gap or an air gap device. An air gap is a physical separation that prevents backflow, effectively protecting the potable water supply from contamination. It is commonly used to ensure that potential contaminants from non-potable sources cannot siphon back into the clean water supply. This method is particularly effective because it adheres to the principle of maintaining a safe distance between the water supply and any potential pollutants. An air gap is often utilized in situations such as between a sink and a drain, where the possibility of backflow could introduce harmful substances. Chlorination is indeed a widely used chemical disinfection method, but it does not rely on a physical barrier and may not be effective against certain contaminants. Flushing can help to remove sediment and stagnant water, but it is not a disinfecting method by itself. UV treatment is effective for disinfection but does not provide the same physical barrier as an air gap, which is often paramount in ensuring that potable water remains uncontaminated. In summary, the air gap method is essential for maintaining the integrity of potable water systems, as it acts as a reliable barrier against contamination.