What tests are first draw samples primarily used for?

First draw samples are primarily used to test for lead and copper levels in drinking water systems. These samples are collected in a way that captures the water that has been sitting in the pipes for a period of time, typically overnight. This methodology is crucial because lead and copper can leach into the water from plumbing materials and fixtures, especially in older infrastructure.

The concentration of these metals is generally highest in water that has been stagnant, making first draw samples essential for accurately assessing potential risks to public health. Results from these tests inform whether corrective actions are needed to reduce levels of these contaminants and ensure that water quality standards are met.

In contrast, other types of tests for pathogens, bacteria, pH, temperature, chlorine, and fluoride generally require different sampling techniques and timelines, as they are not specifically aimed at detecting the accumulative contaminants like lead and copper.