Compliance Corner: 5 Things to Know about EPA Regulations and Liner Standards

If your business handles waste or manages containment systems, you know that EPA regulations aren’t just a stack of rules—they’re the guardrails that keep your operations safe, compliant, and environmentally responsible. At EPI, we spend every day making sure our liners don’t just meet those standards—they exceed them.

Here’s a closer look at five key things you should know about EPA regulations and liner standards, with a few insights from our decades of experience in the field.

1. Composite Liners Are the Standard for Municipal Solid Waste Landfills

Think of a composite liner as a two-part security system for the environment. The EPA requires new municipal solid waste landfills to use a combination of a thick, low-permeability soil layer and a flexible membrane liner on top. The soil acts like a sponge that’s almost impossible for liquids to pass through, and the membrane adds an extra waterproof shield.

Together, they stop contaminated liquid, called leachate, from seeping into the ground and polluting water sources. Even if a project has an alternative design in mind, in most states, this composite approach is still the go-to requirement because it’s proven to work.

2. Double-Liner Systems: Twice the Protection for Hazardous Waste

When you’re dealing with hazardous materials, the EPA doesn’t leave room for error. Hazardous waste landfills, surface impoundments, and certain waste piles must have double-liner systems.

These work like a belt-and-suspenders approach: two separate impermeable liners with a leak detection layer sandwiched between them. If the first liner ever develops a small tear or defect, the second one is ready to catch any leakage before it has a chance to escape. It’s a safety net that buys time to fix issues before they turn into big problems.

3. Liner Thickness: Why “Thin” Isn’t in the Vocabulary

Not all liners are created equal. EPA guidelines spell out minimum thickness requirements: PVC liners can be 30 mil thick, while HDPE liners must be at least 60 mil.

Why the difference? It comes down to the properties of the materials. HDPE is rigid and highly resistant to chemicals, but it needs more thickness to maintain long-term durability. PVC is more flexible, so it can achieve the same performance at a thinner gauge. At EPI, we make sure every liner is fabricated to meet, or exceed, those specs. Because when it comes to environmental safety, there’s no sense in skimping on material.

4. Quality Assurance: Detecting the Invisible

A liner might look flawless to the naked eye, but tiny defects like pinholes or weak seams can undermine the entire system. That’s why EPA regulations call for thorough quality control at every step.

In the factory, each roll is inspected for holes, bubbles, and surface flaws. After installation, specialized electrical integrity surveys can find leaks so small they’re invisible. EPI uses methods like Dual Track Welding, Air Channel Testing, and actual seam samples (not just representative pieces) to make sure every weld holds up under pressure. It’s the difference between “good enough” and bulletproof.

5. One Size Doesn’t Fit All: Match the Liner to the Waste

EPA rules aren’t one-size-fits-all—they’re tailored to the type of waste you’re dealing with.

• Municipal solid waste usually requires a composite liner.

• Hazardous waste almost always demands a double-liner system with leak detection.

• Geosynthetic clay liners (GCLs), which combine bentonite clay with textiles and membranes, are an excellent choice for municipal landfills thanks to their extremely low permeability.

Choosing the wrong system or wrong material can mean costly redesigns or compliance issues. That’s why EPI works closely with project owners to make sure the liner system matches both the waste type and the site conditions.

Why This Matters

EPA regulations can feel complex, but at their core, they’re about protecting clean water and safe soil. By understanding these requirements, you’re not just checking boxes for compliance; you’re building a system that safeguards your community and your project for the long haul.

How EPI Helps You Get It Right

At EPI, we help you get it right by providing custom fabrication of PVC, HDPE, UltraTech, XR-5, and other geomembranes designed to meet your project’s exact needs. Our team uses advanced seam testing and welding methods to ensure unmatched quality assurance, giving you confidence in every liner we deliver. Combined with our deep regulatory expertise, we guide you in selecting the right liner system from the start, helping your project stay compliant and environmentally responsible.