Secondary Containment: Requirements, Options, and Best Practices
Secondary Containment: Requirements, Options, and Best Practices
Secondary containment — a barrier system that captures spills and leaks from primary storage tanks — is required by EPA regulations for many chemical storage installations and recommended as best practice for all above-ground tank storage. This guide covers when secondary containment is legally required, what options are available, and how to design an effective containment system.
Understanding the technical fundamentals behind polyethylene tank construction, ratings, and specifications helps you make better purchasing decisions and avoid costly mistakes. This guide explains what the numbers actually mean and how they affect real-world performance.
When Secondary Containment Is Required
Federal EPA regulations (40 CFR 112 — SPCC Rule) require secondary containment for facilities that store more than 1,320 gallons of oil in above-ground containers, or more than 42,000 gallons in underground tanks. Many states have additional requirements that apply at lower thresholds or cover chemicals beyond oil. Any facility near waterways, wetlands, or drinking water sources faces stricter requirements. When in doubt, assume containment is required — the cost of a containment system is trivial compared to the cost of an environmental cleanup.
Containment Volume Requirements
The standard requirement is containment capacity equal to 110% of the largest single tank in the containment area. For multiple tanks in a single containment area, the capacity must hold the largest tank plus 10% of the aggregate capacity of all other tanks. Additional volume must account for precipitation — if the containment area is uncovered, add the volume of a 25-year, 24-hour rainfall event for your location.
Types of Secondary Containment
Concrete containment dikes — the traditional approach. Poured concrete walls and floor forming a basin around the tanks. Most durable and reliable for permanent installations. Polyethylene containment basins — prefabricated containment trays that sit under individual tanks. Easy to install, no construction required. Sized for specific tank dimensions. Double-wall tanks — a tank within a tank. The outer wall IS the containment. Most compact option but limited to single-tank installations. Flexible containment berms — portable containment for temporary installations or sites where permanent construction isn't feasible.
Containment System Maintenance
A containment system only works if it is intact and functional. Inspect for cracks, deterioration, and damage quarterly. Remove accumulated rainwater promptly — standing water reduces available containment volume and can corrode concrete. Test drain valves if present — a containment area with a stuck-open drain valve provides zero containment. Document all inspections as part of your SPCC plan compliance.
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Key Takeaways
- Always verify your liquid's specific gravity before selecting a tank — exceeding the rated SG is the most common cause of premature tank failure
- Polyethylene tanks are chemically resistant to most substances but NOT all — always check the compatibility chart for your specific chemical
- Proper installation is more important than the tank itself — a premium tank on a bad foundation will fail before a basic tank on a good foundation
- UV stabilizers extend life but don't eliminate UV damage — shade structures are cheap insurance for tanks in full-sun locations
- Temperature matters — polyethylene softens above 120°F and becomes brittle below -40°F. Plan for your climate extremes.
Questions about tank specifications? Call (866) 418-1777 — we speak fluent tank and can translate technical specs into practical guidance for your application.
Understanding Polyethylene Tank Construction
Every polyethylene tank in our catalog is manufactured through rotational molding — a process that creates a seamless, one-piece structure from powdered HDPE resin. The mold rotates on two axes simultaneously while heated, distributing molten resin evenly across all interior surfaces. The result is a tank with no seams, no weld lines, and no potential leak points. This seamless construction is the primary advantage of rotomolded tanks over welded or fabricated alternatives — joints are where tanks fail, and rotomolded tanks have no joints.
The resin itself is not generic plastic. It is a specially formulated compound that includes UV stabilizers (to prevent sun degradation), antioxidants (to prevent thermal degradation during processing and service), and pigments. For potable water applications, the resin meets FDA 21 CFR 177.1520 requirements for food-contact materials. These additives are compounded directly into the resin — not applied as surface coatings — which means the protection extends through the full wall thickness and lasts the life of the tank.
Why Buy from OneSource Plastics?
OneSource Plastics is not just another tank reseller. We are a specialized industrial tank dealer with deep product knowledge, competitive pricing from direct manufacturer relationships, and a commitment to helping you select the right tank for your specific application. Our team handles tank inquiries every day — we know the product lines, the specifications, the common pitfalls, and the solutions.
When you call us, you talk to someone who knows the difference between a 1.5 SG and a 1.9 SG tank, who can explain why a cone bottom is worth the extra cost for your mixing application, and who can tell you exactly what foundation your 2,500-gallon tank needs on your specific soil type. We don't just process orders — we solve liquid storage problems.
Every tank we sell ships with the full manufacturer warranty. We handle freight logistics to all 50 states, and we can coordinate delivery equipment for sites with challenging access. If something goes wrong — a shipping damage claim, a warranty issue, a specification question — we handle it directly. One call to (866) 418-1777 connects you to a real person who can actually help.
Shipping and Delivery Information
We ship polyethylene tanks to all 50 states via the most cost-effective method for each order size. Small tanks (under 150 lbs) ship via UPS or FedEx ground — typically 3-7 business days. Medium tanks ship via LTL freight on pallets — schedule a delivery appointment and request liftgate service if you don't have a loading dock. Large tanks ship via flatbed — you'll need a forklift or equipment for unloading.
Freight cost for polyethylene tanks is driven by size (cubic feet), not weight. A 1,000-gallon tank is physically large — over 5 feet in diameter and 6 feet tall — and takes significant truck space even though it weighs only 100-200 pounds empty. We quote freight individually for each order because rates vary significantly by destination, carrier, and accessorial services like liftgate and residential delivery.
For the most accurate freight quote, call us with your zip code and the products you're considering. We ship daily and know which carriers provide the best rates and service to each region of the country.