Municipal solid waste, commonly called MSW or simply “trash,” is the everyday garbage generated by households, businesses, schools, and other community sources. In the United States, this added up to 292.4 million tons in 2018, or about 4.9 pounds per person per day. It includes everything from food scraps and junk mail to old furniture and plastic packaging, but it does not include industrial hazardous waste, construction debris, sewage, or radioactive materials.
What Counts as Municipal Solid Waste
MSW covers two broad streams: household waste and commercial waste. Household waste is anything discarded from a residence, regardless of how toxic it might seem (old batteries, cleaning products, leftover paint). Commercial waste comes from offices, restaurants, retail stores, hotels, and institutions like schools and hospitals. According to EPA data, the split between these two sources is roughly even. Residential sources account for about 46 percent of total MSW generation, while commercial sources make up around 54 percent, though these figures vary by state.
Several major waste streams are handled separately and fall outside the MSW category. Hazardous industrial waste, construction and demolition debris, mining waste, agricultural waste, and sewage are all regulated under different rules. Radioactive materials are excluded entirely, governed instead by atomic energy law. A notable edge case: a construction landfill that accepts residential lead-based paint waste but no other household trash is not classified as a municipal solid waste landfill.
What’s Actually in Your Trash
Paper and paperboard make up the single largest share of MSW at 23.1 percent. Food waste runs a close second at 21.6 percent. Yard trimmings (grass clippings, leaves, branches) account for 12.1 percent. Together, these organic materials represent well over half of everything Americans throw away.
The rest breaks down like this:
- Plastics: 12.2 percent
- Metals: 8.8 percent (aluminum cans, steel containers, appliances)
- Wood: 6.2 percent
- Glass: 4.2 percent
The remaining fraction includes textiles, rubber, leather, and miscellaneous inorganic materials. This composition matters because each material has a different recycling potential, decomposition timeline, and environmental footprint. Food and yard waste, for example, break down relatively quickly in a landfill but produce methane as they decompose. Plastics barely decompose at all but take up growing landfill space.
Where It All Goes
Half of all U.S. municipal solid waste ends up in landfills. About 32 percent is recycled or composted, diverting roughly 93.9 million tons away from landfills and incinerators. That recovery rate is about 2.8 times what it was in 1990. The remaining 12 percent is burned in waste-to-energy facilities that generate electricity from combustion.
Of the material that gets recovered, about 27 percent is composted (mostly food and yard waste) and the rest is recycled into new products. Metals like aluminum and steel have some of the highest recycling rates because they can be melted down and reused indefinitely without losing quality. Paper and cardboard are also widely recycled, though fibers degrade with each cycle. Plastics have the lowest recovery rates, partly because there are so many different resin types that sorting and reprocessing is expensive.
Environmental Impact of Landfilled Waste
When organic materials like food scraps and paper decompose in a landfill, they produce landfill gas, a mixture that is roughly half methane and half carbon dioxide. Methane is a potent greenhouse gas, trapping far more heat in the atmosphere than carbon dioxide over a 20-year period. MSW landfills are the third-largest source of human-caused methane emissions in the United States, responsible for approximately 14.4 percent of those emissions as of 2022.
Many modern landfills capture some of this methane and either flare it (burn it off) or use it to generate electricity. But capture systems don’t collect everything, and older or poorly maintained landfills can release significant amounts unchecked. This is one reason diverting food waste to composting facilities, where it breaks down aerobically and produces far less methane, has become a policy priority in many states.
Landfills also pose risks from leachate, the liquid that forms when rainwater filters through decomposing waste. Modern landfills use liner systems and leachate collection to prevent contaminated liquid from reaching groundwater, but these protections have a finite lifespan. The long-term management of closed landfills remains an ongoing cost for municipalities.
How Much Waste Is Growing
Per capita MSW generation in the U.S. jumped 8 percent in a single year, from 4.5 pounds per person per day in 2017 to 4.9 pounds in 2018. That increase reflects both economic activity (people buy and discard more when the economy is strong) and the growing prevalence of single-use packaging, particularly from e-commerce and food delivery.
Globally, the trajectory is steeper. Researchers estimate that worldwide MSW generation will reach between 2.89 and 4.54 billion tons by 2050, representing a 26 to 45 percent increase over 2019 levels. The range depends on assumptions about population growth, urbanization rates, and how quickly developing nations adopt waste reduction policies. Much of the growth is expected in sub-Saharan Africa and South Asia, where rapid urbanization is outpacing waste management infrastructure.
These projections put pressure on every level of the waste hierarchy: reducing what gets produced in the first place, reusing materials, recycling and composting what remains, and only landfilling or incinerating what truly has no other destination. For individuals, the most effective lever is at the top of that hierarchy. The trash that never gets generated never needs to be managed.