If you’ve opened your garbage can in the middle of summer and found it crawling with maggots, you already know it’s one of the worst things you’ll encounter on a Tuesday morning. The good news is that maggots in a garbage can are not random. There’s a straightforward explanation for how it happens, and once you know it, you can actually do something about it.
Where Maggots Come From
Maggots are the larval stage of the common housefly. A fly lands on your garbage can, finds rotting organic material inside, and lays eggs directly onto it. Those eggs hatch into maggots. The maggots feed, develop, and become adult flies. That’s the whole cycle.
One fly is enough. A single housefly can lay up to 500 eggs in her short lifetime, in batches of 75 to 150 at a time, over just a few days. According to the University of Michigan’s Animal Diversity Web database, in warm weather those eggs hatch within 8 to 12 hours. At peak summer temperatures, the full cycle from egg to adult fly can complete in as few as 7 to 10 days.
That means one fly laying eggs early in your collection cycle can produce multiple generations of maggots before the garbage truck comes around again. Knowing what causes maggots in a garbage can is the first step to actually preventing them.
Why Maggots in Your Garbage Can Are Worse Here Than in Most Places
Fly development is tied directly to temperature. The peak range is 25 to 30 degrees Celsius, which is exactly what Kitchener, Cambridge, and Waterloo get from June through September (and sometimes beyond).
In 2025, Waterloo Region logged 34 days above 30 degrees Celsius. The historical average is 11. According to CBC News Kitchener-Waterloo, using data from the University of Waterloo’s weather station, it was the fourth-hottest summer on record since 1917. Warmer summers mean faster hatching, faster development, and more generations per season.
The collection schedule makes it worse. The Region of Waterloo picks up black garbage cans every other week. That’s a 14-day window. A fly that gets into your garbage can and lays eggs two days after collection has nearly two full weeks for her eggs to hatch, develop, and start the cycle again. By pickup day, what started with one fly can be a full infestation.
The new black garbage cans the Region rolled out in March 2026 are large, dark, and sealed. Dark containers sitting in direct sun trap heat and humidity inside. Both accelerate maggot development.
What Flies Are Actually Attracted To
Flies don’t find your garbage can by looking for it. They smell it. Decomposing organic material produces gases that flies detect from a distance. Meat packaging, fish waste, fruit and vegetable scraps, and food liquids are the strongest attractants.
Once a fly finds a suitable spot, it leaves chemical traces that draw other flies to the same location. It’s part of why a garbage can that’s had a maggot problem tends to have one over and over again.
The green organics garbage can is often a worse problem than the black one. It’s collected weekly, which sounds better, but it also means it never fully dries out. It gets fresh food waste added every week, and the sealed lid keeps it warm and damp between collections. That’s close to ideal conditions for maggots to develop.
Why It’s Not Just a Nuisance
Maggots in a garbage can are disgusting, but an even bigger issue is what happens once the maggots develop into adult flies. A 2018 systematic review published in BMC Public Health found that over 100 pathogens have been associated with the housefly, including bacteria, viruses, fungi, and parasites. Specific bacteria found in houseflies include E. coli, Salmonella, Shigella, and Cryptosporidium parvum. For households with young children, elderly family members, or someone who is pregnant, those bacteria carry serious health risks.
Adult flies carry those pathogens on their bodies and deposit them on every surface they land on. Kitchen counters, food preparation areas, anywhere in the house they get into. The garbage can is where it starts.
If your garbage can smells bad even when it’s empty, that’s part of the same problem. The organic residue that attracts flies also feeds the bacteria that produce odour. There’s more on that in our post on why garbage cans smell so bad.
How to Actually Reduce the Problem
Keep the lid closed. Flies get in through gaps around the lid, and the Region’s new garbage cans are designed to seal well. Use that.
Wrap meat packaging tightly before it goes in, or freeze meat scraps and add them to the can on collection morning. Meat is the strongest attractant by far.
Ensure that your garbage cans are cleaned regularly. A garden hose, while better than nothing, only rinses out surface level grime. It doesn’t touch the bacteria and buildup that have worked into the plastic over time. Getting rid of that requires hot water and pressure. It’s a significant job, and it needs to happen regularly, not once.
For more on what’s actually building up inside an uncleaned garbage can and what a proper cleaning involves, see our complete guide to garbage can cleaning in Waterloo Region.
We Can Help
We Clean Garbage Cans cleans residential garbage cans in Kitchener, Cambridge, and Waterloo. We show up on your garbage day after the truck has been, clean both cans using 200°F hot water and high pressure, and use a closed-loop wastewater system so we’re not leaving a mess that runs into your driveway or the storm drains.
A clean garbage can won’t make flies disappear completely from all the yards around your neighbourhood. But it removes the residue and odour that give them a reason to choose yours.
Ready for clean garbage cans? Sign up today. Just fill out the form and we’ll be in touch shortly to confirm your information and get you added to your neighbourhood route.