Which statement is true regarding Secondary Maximum Contaminant Levels (SMCL)?

Secondary Maximum Contaminant Levels (SMCL) are non-mandatory water quality standards established by the U.S. Environmental Protection Agency (EPA) to guide public water systems in managing aesthetic and operational aspects of drinking water, such as taste, odor, and color. While SMCLs aim to promote better water quality, they do not have the force of law like primary maximum contaminant levels (MCLs), which are designed to protect public health by regulating substances that pose health risks.

Given that SMCLs serve to address issues that are generally not health-related, but rather focus on improving the aesthetic qualities of drinking water, they do not require mandatory testing or enforcement. This characteristic differentiates them from enforceable regulations and makes them advisory in nature, providing recommendations rather than mandates. Hence, the statement about SMCLs being non-mandatory water quality standards accurately reflects their role in water treatment and public health policy.