The number inside the recycling triangle on plastic containers is not a recycling promise. It's a resin identification code that tells you what type of plastic the item is made from. Whether your local facility actually recycles that type is a completely different question, and the answer varies by municipality.
The seven codes
#1 PET/PETE (Polyethylene Terephthalate): Water bottles, soda bottles, food containers. Widely recycled. This is the easy one. Most curbside programs accept it. Recycled into fibers (polyester clothing), new bottles, and carpet.
#2 HDPE (High-Density Polyethylene): Milk jugs, detergent bottles, shampoo bottles. Widely recycled. Along with #1, this is the most commonly recycled plastic. Becomes new bottles, lumber, pipes, and playground equipment.
#3 PVC (Polyvinyl Chloride): Pipes, window frames, some food wrap. Rarely recycled in curbside programs. PVC contaminates other plastic streams and releases harmful chemicals when melted. Most facilities reject it.
#4 LDPE (Low-Density Polyethylene): Grocery bags, squeezable bottles, bread bags. Sometimes recycled. Many grocery stores have bag collection bins for #4. Curbside programs often reject it because film plastics jam sorting equipment.
#5 PP (Polypropylene): Yogurt containers, bottle caps, straws, takeout containers. Increasingly recycled. This was historically difficult to recycle, but acceptance has grown. Check your local program.
#6 PS (Polystyrene): Foam cups, takeout containers, packing peanuts. Rarely recycled. Expanded polystyrene (Styrofoam) is especially problematic: it's 95% air, making it uneconomical to transport. Very few facilities accept it.
#7 Other: Everything else, including polycarbonate, nylon, and bioplastics. Generally not recycled. This is the catch-all category and most facilities won't touch it.
The contamination problem
A single greasy pizza box in a paper recycling batch can contaminate the entire load. Food residue on plastic containers causes the same issue. Rinse containers before recycling. Remove food residue. Remove caps if your program requires it (many now accept caps on bottles).
"Wish-cycling," putting items in the recycling bin hoping they'll be recycled, causes more harm than good. Non-recyclable items contaminate loads, increase processing costs, and can cause entire batches to be sent to landfill. When in doubt, throw it out. Better to lose one recyclable item than contaminate a truckload.
What actually happens to your recycling
After collection, recyclables go to a Materials Recovery Facility (MRF). They're sorted by type using a combination of manual labor, optical sorters, magnets (for steel), eddy currents (for aluminum), and air classifiers (for paper). Sorted materials are baled and sold to processors.
The economics of recycling depend on commodity prices. When oil is cheap, virgin plastic is cheaper than recycled plastic, and recycling processors struggle to find buyers. When oil is expensive, recycled plastic becomes economically competitive. This market volatility is why recycling programs expand and contract over time.
Local variations
Your city's recycling program determines what's accepted, not the plastic code. A city with a modern MRF might accept #1 through #7. A rural area with limited infrastructure might only take #1 and #2. Check your municipality's website for the actual list.
I built a recycling guide at zovo.one/free-tools/recycling-guide that explains material types, preparation requirements, and general acceptance rates. It's a reference for making sorting decisions quickly, though you should always verify with your local program.
I'm Michael Lip. I build free developer tools at zovo.one. 500+ tools, all private, all free.
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