What doesn’t get measured doesn’t get done. But pet waste doesn't get measured!
Calculating how much dog and cat waste is streamed to landfills in the U.S. alone is difficult to do and the amount increases each year. There are no comprehensive official statistics, but here is one attempt to quantify trashed pet waste based on available data.
Dogs
The Environmental Protection Agency estimates that the typical dog generates three quarters of a pound of waste per day – or 274 pounds per year. Therefore 77 million dogs produce 57,750,000 pounds (28,875 tons) of waste per day or 10,539,375 tons per year.
How much is trashed? A total of 80.7% of the US population live in urban areas. That calculates to approximately 62,139,000 urban dogs. According to surveys, roughly 60% of dog owners say that they pick up after their dogs. Sixty percent of 62,139,000 dogs brings the number of urban dogs with owners who pick up their waste to 37,283,400. Those dogs produce 27,962,550 pounds (13,981.275 tons) of waste per day or 5,103,165.375 tons per year. Much of this trashed waste is comingled with plastic pick-up bags.
Cats
Cats poop less and most city cats’ waste is co-mingled with clay litter. No organization has undertaken an official study of the amount of waste cats produce, but an informal measure reported by Rose Seemann in The Pet Poo Pocket Guide: How to Safely Compost and Recycle Pet Waste indicates that an average cat leaves around .3 pounds of waste/litter per day for disposal. Approximately 70% of the 54 million U.S. cats are kept indoors. These 37,800,000 indoor cats produce 11,340,000 pounds (5.670 tons) of waste day or 2,069,550 tons per year.
This does not include co-mingled plastic and bulk cat litter resulting from litter box dumps. Disposal of the litter itself presents challenges. According to Judd H. Alexander in 1993’s In Defense of Garbage, over 2 million tons of cat litter ends up in landfills each year more than 2 million tons of clay litter is disposed of each year in the United States. That was 1996, but we’ll use that conservative number in our stats. So the sheer volume of used cat litter has a significant impact on landfills
Disposal of the litter itself presents challenges. According to Judd H. Alexander in 1993’s In Defense of Garbage, Americans dispose of more than 2 million tons of clay litter each year. That was 1996, but we’ll use that very conservative number for bulk litter disposal in our stats.
Total pet waste to landfills
More than five million tons of dog waste plus two million tons of cat waste plus two million tons of additional disposed litter totals approximately nine million tons of pet waste streamed to U.S. landfills each year.*
Pet waste compared to other U.S. waste
When reviewing the data for waste quantities below, keep in mind that anaerobic degradation of organics such as pet waste in landfills results in methane emissions that impact air quality.
“Each ton of organic waste disposed of as landfill and broken down by anaerobic fermentation releases about one ton of carbon dioxide equivalents (CO2–e) of greenhouse gases, mostly in the form of methane.”
Municipal solid waste (MSW) landfills are the third-largest source of human-related methane emissions in the United States, accounting for approximately 15.1 percent of these emissions in 2018.
In “Strategies for Reducing Degradable Organic Wastes in Landfills" the Wisconsin Department of Natural Resources states: “Current landfill designs and practices do not provide for degradation of landfilled organic wastes within a defined and reasonable timeframe. Un-degraded organic wastes can potentially cause future environmental or economic impacts if the landfill gas and leachate collection and containment systems (cap and/or liner) fail at some time in the future. Potential economic burdens and environmental risks associated with these undegraded wastes will be largely borne by future generations.”
Below: from U.S. Environmental Protection Agency: 2018 Facts and Figures about Materials, as posted March 2021
Printed in black: direct data from EPA 2018 Facts and Figures (disposal of traditionally quantified materials) Printed in red: estimated pet waste in residential waste stream - data is contradictory! Based on the math of dog & cat waste production = 9 tons* contradicts percentage reported by two recent Canadian waste audits**.
Municipal Solid Waste
Materials Landfilled (in % of total MSW % recycled % combusted with
(millions of tons) energy recovery
Food 35.28 21.5 Composting 21.85
6.08
Other
management
41.57
Plastics 26.97 12.20 4.47 16.27
Paper/ 17.22 23.05 66.54 12.16
paperboard
Metals 13.93 8.76 12.62 8.54
Wood 12.15 6.10 4.49 8.22
Dog & cat 12?* 12?*
waste
Textiles 11.3 5.80 Rubber + 9.32
leather +
textiles
6.05
Yard 10.53 12.11 52.35 7.44
trimmings
Glass 7.55 4.19 4.43 4.75
Rubber & 4.99 3.13 Rubber + 7.24
leather leather +
textiles
6.05
Misc. 3.27 1.39 0 2.32
inorganic
Other 2.93 1.56 1.40 1.91
* Six and a half million tons of dog waste plus 3.6 million tons of cat waste plus two million tons of disposed litter totals approximately 12 million tons of pet waste streamed to U.S. landfills each year.
** “We have been doing a series of waste audits on residential garbage. We’ve done two so far and the third is slated to be done August/September of 2018. What we did find in both of those audits, consistently, is that 12 per cent of what is in the residential waste is pet waste.” Susan Grimm, team leader, City of Airdrie (Alberta) Waste and Recycling Services
Summary
This data projection shows that pet waste is under the radar. But the need for accurate data on the quantity and its relationship to other MSW is essential to developing standardized best practices for diverting pet waste from landfills.
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