Understanding Water Quality Standards: PHGs vs. MCLs

Understanding Water Quality Standards: PHGs vs. MCLs

At Greenfield Water Solutions, we know that many of our customers prioritize the highest standards of water quality. A common question we receive is about Public Health Goals (PHGs), also known as Health Guideline Levels (HGLs), and how these compare to Maximum Contaminant Levels (MCLs). In this article, we’ll clarify the difference between these two standards and explain why most filters, including reverse osmosis (RO) systems, ultrafiltration, and gravity feed filters, typically adhere to MCL standards.

What Are Public Health Goals (PHGs) or Health Guideline Levels (HGLs)?

PHGs, or Health Guideline Levels, are set by the Office of Environmental Health Hazard Assessment (OEHHA). They represent the ideal level of a contaminant in drinking water at which no adverse health effects are expected. These guidelines are calculated based on a lifetime exposure to the contaminant—essentially, the level at which a person could drink the water daily for 70 years without experiencing significant health risks.

For chemicals that can cause cancer, PHGs are typically set at a “one-in-one-million” risk level. This means that if one million people were exposed to the contaminant every day for 70 years, only one person would be expected to develop cancer as a result of that exposure.

It’s important to note that PHGs are not regulatory standards. Instead, they are aspirational health goals designed to guide improvements in water quality.

What Are Maximum Contaminant Levels (MCLs)?

In contrast, MCLs are enforceable regulatory standards set by the Environmental Protection Agency (EPA) under the Safe Drinking Water Act. MCLs represent the highest allowable level of a contaminant in drinking water, balancing ideal health outcomes with practical considerations like treatment technology and cost.

MCLs are set as close to PHGs as feasible while accounting for the limitations of current filtration technologies and the costs associated with achieving near-zero contaminant levels. Although MCLs may not always reach the low levels recommended by PHGs, they still ensure that the water is safe for public consumption.

Why Do Most Filters Adhere to MCLs?

While PHGs represent the ideal contaminant levels, achieving them with current filtration technology is often not feasible. Most water filters, including high-quality systems like reverse osmosis, ultrafiltration, and gravity feed filters, are designed to meet MCL standards, which are realistic, achievable benchmarks that ensure water safety.

PHGs are set based on the best-case scenario for health, but achieving these levels requires extremely advanced technologies that can be cost-prohibitive for most households. That’s why filters typically adhere to MCLs—these standards provide a balance between health protection and affordability.

Addressing Customer Concerns

Some of our customers use PHGs to evaluate filter effectiveness. However, it’s important to remember that PHGs are meant to serve as goals rather than strict performance metrics for filtration systems. Achieving PHG levels would require frequent filter changes and expensive technology that may not be practical for everyday use.

At Greenfield Water Solutions, we focus on reducing contaminants to meet or exceed MCLs, ensuring safer, healthier water for your home. We are committed to continuous improvement and the development of more advanced filtration methods as our understanding of water contaminants evolves.

Understanding What’s in Your Water

We recommend using resources like the EWG Tap Water Database to get a clearer picture of what contaminants may be present in your local water supply. This tool can help you understand the water quality in your area and identify the best filtration solution for your needs.

Conclusion

At Greenfield Water Solutions, we are dedicated to providing the highest quality water filtration systems that meet or exceed MCL standards. While PHGs are valuable for understanding potential health risks, MCLs offer practical, enforceable benchmarks for ensuring safe drinking water. As we continue to develop and refine our filtration technologies, our commitment to cleaner, healthier water remains strong.