The Role of Corrosion Control in Preventing Lead Exposure

When we talk about the safety of our drinking water, the conversation often centers on lead pipes and the urgent need for their replacement. While removing lead infrastructure is the only permanent solution, there is a vital, invisible process happening in the background that keeps millions of households safe while those replacements are underway: corrosion control.

If you have ever wondered why your city adds certain minerals to your water or why officials focus so heavily on “pH balance,” you are looking at the essential science of corrosion control.

What Is Corrosion Control?

At its simplest, corrosion control is the practice of treating drinking water to prevent it from dissolving the materials it touches as it travels through pipes.

EPA

When water is “aggressive”—meaning it is acidic or lacks certain minerals—it acts like a mild solvent. As it flows through aging infrastructure, it can pull metal atoms, specifically lead, from the walls of pipes, solder joints, and brass fixtures. This process is called leaching.

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Corrosion control is the process of modifying the water’s chemistry at the treatment plant to form a protective barrier between the water and your pipes. By doing this, the water becomes “inert” or less reactive, meaning it flows through your plumbing without stripping away harmful metals.

Providence Water

The Chemistry Behind the Shield

How do cities actually stop metal from dissolving? They typically use two primary methods:

1. pH Adjustment

The pH level of water measures its acidity. Acidic water (low pH) is naturally more aggressive and can easily dissolve metals. By adding substances to raise the pH—making the water slightly more alkaline—utilities can significantly reduce its corrosive potential. This not only protects the pipes but also helps strengthen any existing protective coatings that may have formed naturally over time.

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2. Orthophosphate Addition

This is perhaps the most well-known tool in a water utility’s arsenal. Orthophosphate is a food-grade additive—the same type of mineral found in many common foods—that utilities mix into the water supply. When it reaches your pipes, it reacts with the lead surface to create a thin, stable mineral coating (often called a “scale”). This coating acts as a physical shield, essentially “insulating” the lead from the water. Even if your home is connected by old lead service lines, this protective layer ensures that the water passing through the pipe is much less likely to become contaminated.

Cleveland Water Department

Why Corrosion Control Is a Public Health Priority

You might wonder: if we know pipes are made of lead, why not just replace them all tomorrow? The reality of our nation’s cities and infrastructure is that there are millions of miles of pipe, and replacement is a massive, multi-year logistical undertaking.

Corrosion control serves as a critical “bridge” to safety. It provides immediate, system-wide protection for every household in the utility’s service area. For families living in older homes with plumbing and lead concerns, effective corrosion control means their daily risk of lead exposure is kept significantly lower while the community plans for the long-term goal of total pipe replacement.

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The EPA’s Role and Your Safety

The Environmental Protection Agency (EPA) mandates corrosion control under the Lead and Copper Rule (LCR). This federal regulation requires water systems to:

EPA

Monitor water quality parameters (like pH and alkalinity) throughout the distribution system. Canada.ca
Perform regular tap sampling at high-risk homes to ensure that corrosion control treatments are effectively keeping lead levels low. Clean Water Action
Optimize treatment if lead levels at the tap exceed specific “action levels.” EPA

These safeguards are designed to ensure that your utility isn’t just adding chemicals to the water, but is scientifically verifying that those chemicals are working as intended.

What Residents Can Do

Corrosion control is a powerful tool, but it works best when paired with responsible household water habits. Because lead is a persistent health concern, you can further reduce your risk by following these proven practices:

Flush the Tap: If your water has been sitting in your pipes for 6 hours or more, run your cold water tap for 3 to 5 minutes. This purges the stagnant water that has been in contact with your home’s internal plumbing.
Use Cold Water Only: Never use hot tap water for drinking, cooking, or making baby formula. Heat accelerates the corrosion process and can increase the amount of lead in your water. EPA
Stay Informed: Your utility’s annual Consumer Confidence Report (CCR) will contain information about their corrosion control measures. Check your utility’s website to stay updated on your local water quality.

If you have questions about your specific water system or need help interpreting your local water quality reports, our FAQ page is a great place to start. For ongoing news about infrastructure advocacy and safety tips, be sure to visit our blog regularly.

If you suspect your water quality is declining or have specific concerns about your property, please contact us for guidance. Together, we can ensure that our homes remain safe while we advocate for the long-term infrastructure improvements our communities deserve.

Disclaimer: This article is for informational purposes only and does not constitute professional medical, engineering, or plumbing advice. If you have concerns about the safety of your drinking water, always consult with your local water utility or a certified environmental testing laboratory.

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