California Registered Environmental Health Specialist (REHS) Disaster Management Practice Test

Protecting drinking water sources from human waste by keeping latrines a safe distance away is the key idea. Pit privies can release pathogens through leachate that moves through soil or via surface runoff, so placing them at a safe setback from lakes, streams, and wells reduces the chance that contaminated water will be consumed or used. The 100-foot minimum is a commonly taught emergency guideline because it strikes a practical balance between rapid setup in disaster conditions and ensuring a protective buffer for groundwater and surface water sources. A smaller distance, like 50 feet, increases risk of contamination, while distances like 150 or 200 feet go beyond the minimum and aren’t required in this standard scenario. If water tables are shallow, soils are sandy, or flood risk is high, you would want to increase this setback or take additional water protection measures.