Most curbside recycling programs reliably accept only two types of plastic: #1 (PET) and #2 (HDPE). These are the water bottles, soda bottles, milk jugs, and detergent containers you use every day. Beyond those two, acceptance varies wildly depending on where you live, and the majority of other plastics end up in landfills regardless of what the number inside the triangle suggests.
The Two Plastics Almost Always Accepted
#1 PET and #2 HDPE are the workhorses of plastic recycling. PET shows up in disposable drink bottles, prepared-food containers, and frozen-food trays. HDPE is the opaque, sturdier plastic used for milk jugs, household cleaner bottles, and some food containers. Both are accepted by the vast majority of municipal recycling programs in the United States.
Even so, the actual recycling rates for these two are surprisingly low. The EPA reports that PET bottles and jars had a recycling rate of 29.1% in 2018, and HDPE natural bottles came in at 29.3%. That means roughly 70% of even the most recyclable plastics still don’t make it through the system, lost to contamination, sorting errors, or simply never making it into a recycling bin.
Plastics That Depend on Your Location
#5 polypropylene (PP) is a common source of confusion. It’s found in yogurt cups, soft-drink cups, straws, and takeout containers. Many people assume it’s recyclable because it carries a resin code, but fewer than 30% of Americans have access to a recycling system that actually accepts it. If your local program doesn’t list #5 specifically, putting it in the bin does more harm than good because it becomes a contaminant in the recycling stream.
#4 low-density polyethylene (LDPE) is the thin, flexible plastic used for grocery bags, bread bags, and produce bags. Most curbside programs reject it because it wraps around the machinery at sorting facilities and causes jams. Many grocery stores, however, collect LDPE bags separately in drop-off bins near the entrance. If you want to recycle plastic bags, that store drop-off is typically your only option.
Plastics Rarely or Never Recycled
#3 PVC is found in some detergent bottles, shampoo bottles, and children’s toys. It’s significantly harder to recycle than PET or HDPE, and most municipal programs don’t accept it. PVC contains chlorine, which complicates processing and can contaminate batches of other recyclable plastics.
#6 polystyrene, commonly known as Styrofoam, appears in takeout containers, disposable coffee cups, and packing peanuts. It is generally not accepted in recycling programs. Polystyrene is lightweight and bulky, making it expensive to transport relative to the material recovered, and it breaks into small pieces that are difficult to sort.
#7 is a catch-all category for everything else, including polycarbonate, certain bio-based plastics, and multi-layer packaging. These plastics are almost never recyclable through curbside programs. The mixed composition makes them incompatible with standard sorting and reprocessing equipment.
Why the Triangle Doesn’t Mean “Recyclable”
The numbered triangle on plastic packaging is a resin identification code, not a recycling symbol. It tells recyclers what type of polymer the item is made from, but it says nothing about whether your local facility can process it. The EPA itself acknowledges that confusion about what materials can be recycled is one of the biggest challenges facing the U.S. recycling system. Many consumers see the triangle and toss the item in the bin, which leads to contamination that can cause entire loads of otherwise recyclable material to be sent to landfill.
Color adds another layer of complexity. Black plastic containers, even when made from recyclable polymers like PET or HDPE, often can’t be recycled in practice. The sorting machines at recycling facilities use near-infrared light to identify different plastic types, and black carbon dye absorbs that light, making the plastic invisible to the sensors. Black takeout trays and black plastic lids frequently get sorted into the reject pile for this reason alone.
How to Prepare Plastics for Recycling
Getting your recyclables accepted starts with a few simple habits. Empty containers completely and give them a quick rinse to remove food residue. You don’t need to scrub them spotless, just knock out the obvious leftovers. Food-contaminated plastics are one of the top reasons recyclable material gets rejected at processing facilities.
Leave caps on bottles. This is a shift from older guidance, but modern recycling equipment handles attached caps more effectively than loose ones, which are small enough to fall through sorting screens and get lost. Keep labels on as well; they’re removed during processing.
Never bag your recyclables in a plastic bag before placing them in the bin. Bags clog sorting machinery and force workers to pull them out by hand, slowing the entire operation. Place items loose in the bin. And when in doubt about a specific item, check your local program’s accepted materials list rather than guessing. “Wish-cycling,” tossing something in the bin hoping it gets recycled, creates real problems downstream.
What Happens to Plastics That Can’t Be Recycled Traditionally
Standard recycling is a mechanical process: plastics are shredded, washed, melted, and reformed into pellets. This works well for clean, single-polymer items like PET bottles, but it struggles with mixed, contaminated, or multi-layer plastics. Each time plastic goes through mechanical recycling, the polymer chains shorten slightly, reducing quality. This is why a recycled bottle often becomes a lower-grade product like carpet fiber or polyester fabric rather than a new bottle, a process sometimes called downcycling.
Chemical recycling takes a different approach. Instead of melting plastic, these processes break polymers down to their molecular building blocks using heat, solvents, or chemical reactions. This allows them to handle plastics that mechanical recycling can’t touch: mixed plastic waste, contaminated packaging, multi-layer films (like chip bags or juice pouches), and even ocean-collected plastic litter. Researchers have demonstrated processes that can separate individual polymers from complex mixtures of electronic waste plastics and deconstruct multi-layer food packaging into materials comparable to virgin plastic. Some facilities convert mixed plastic waste into a petroleum-like oil through high-heat processing, which can then be refined into raw materials for new plastics or fuels.
These technologies are still scaling up and aren’t yet widely available, so they don’t change what you can put in your curbside bin today. But they represent a path for the large volume of plastic that currently has no recycling option.
A Quick-Reference Guide by Number
- #1 PET: Widely accepted curbside. Water bottles, soda bottles, food containers.
- #2 HDPE: Widely accepted curbside. Milk jugs, detergent bottles, household cleaner bottles.
- #3 PVC: Rarely accepted. Some bottles and toys. Check locally.
- #4 LDPE: Not typically accepted curbside. Plastic bags and wraps can go to grocery store drop-off bins.
- #5 PP: Accepted in some areas, but under 30% of Americans have access. Yogurt cups, straws, food containers.
- #6 PS (Styrofoam): Generally not accepted. Takeout containers, disposable cups.
- #7 Other: Almost never accepted curbside. Mixed or specialty plastics.
Your single most useful step is checking your municipality’s specific accepted materials list. Programs vary enough from city to city that national generalizations only get you so far. Most cities publish this on their waste management website, and some even offer apps that let you search by item.