Q:What are the safest, most durable potable water coatings?

When specifying pipelines for potable (drinking) water, the selection criteria extend far beyond simple corrosion protection. The primary responsibility is to ensure public health by preserving the quality and safety of the water being transported.

A critical question we address for municipal engineers and water authorities is which coating and lining systems are both certified as safe for drinking water and durable enough to guarantee a long service life. From our perspective, this is a matter of both uncompromising compliance and proven performance.

The Non-Negotiable Requirement: Certification to NSF/ANSI/CAN 61

Before we discuss specific coating types, the single most important requirement must be addressed: safety certification.

Any material, coating, or lining that will come into contact with drinking water must be certified to NSF/ANSI/CAN 61: “Drinking Water System Components – Health Effects.” This is the internationally recognized standard that ensures a product will not leach harmful levels of contaminants, metals, or chemicals into the water.

Our expert guidance: Always demand proof of this certification for any internal lining you are considering. This is a non-negotiable benchmark for ensuring public safety and meeting regulatory requirements.

Recommended Lining and Coating Systems

Once the NSF/ANSI/CAN 61 certification is confirmed, you can choose from several excellent, high-performance systems for the pipe’s interior and exterior.

Internal Linings (Water-Contact Surfaces)

1. Cement Mortar Lining This has been the waterworks industry’s trusted solution for decades, and for good reason. A layer of cement mortar is centrifugally applied to the pipe’s interior, creating a dense, smooth surface.

• Advantages: It creates a stable, inert barrier that not only prevents the steel from corroding but also actively passivates the steel surface. It is exceptionally durable, long-lasting, and highly cost-effective, especially for large-diameter water transmission mains.

2. Liquid-Applied Epoxy Linings These systems consist of a two-part, 100% solids (solvent-free) epoxy that is spray-applied to the pipe’s interior.

• Advantages: Liquid epoxies create an extremely smooth, glossy surface that can improve the pipe’s hydraulic efficiency (known as the Hazen-Williams “C” factor), potentially reducing long-term pumping costs.
• Critical Factor: It is essential that the specific epoxy formulation is certified to NSF/ANSI/CAN 61 and is applied under strict quality controls to ensure correct thickness and a full cure.

3. Fusion Bonded Epoxy (FBE) Linings This is a factory-applied, thermosetting powder coating. As with liquid epoxies, the specific FBE powder used must be certified for potable water contact.

• Advantages: FBE provides a very tough, damage-resistant, and consistent internal lining. The factory-controlled application process ensures a high degree of quality control and a reliable finish. It’s a premium choice for combining water safety with a robust, durable surface.

External Coatings (Protection from the Environment)

While the internal lining protects the water, the external coating protects the pipe from soil corrosion, moisture, and other environmental factors. Since these coatings do not contact the drinking water, they do not require NSF certification. Excellent, high-performance choices include:

• 3LPE / 3LPP Systems
• Fusion Bonded Epoxy (FBE)
• Polyurethane Coatings

The choice of external coating depends on the soil conditions, installation method, and operational environment.

The Allland Steel Commitment to Water Safety

Protecting our water resources is a shared responsibility. At Allland Steel, we provide pipeline solutions that meet the stringent safety and performance standards required for modern water infrastructure. We can supply pipes with a range of NSF/ANSI/CAN 61 certified internal linings and highly durable external coating systems.

Our specialists are ready to help you analyze your project’s requirements to engineer the optimal and safest pipeline solution.

Contact an Allland Steel specialist to discuss your potable water pipeline project.