Mosquitoes Eating You Alive? Check Your Eavestroughs — The Standing Water On Your Own Property Is The Problem

You are standing in your own back yard in Spruce Grove in the middle of July, and you are being eaten alive. It feels like the mosquitoes are coming from the river valley, or the farmer’s field down the road, or anywhere but here. Often they are not. A meaningful share of the mosquitoes biting you on your own deck were born on your own property — in an eavestrough packed with last fall’s leaves, in a rain barrel with no screen, in a bird bath nobody has emptied since May. Edmonton has more than 30 species of mosquito, and the common summer biter can go from egg to adult in about five days. That is the entire problem, and the entire opportunity.

The City Treats The Ditches. Nobody Treats Your Yard.

The City of Edmonton runs a targeted Ditch and Ground Control program that goes after mosquito larvae in roadside ditches and other ground habitats before they hatch, using Health Canada-approved biological pesticides that kill larvae without harming people, pets or wildlife. It is a genuinely good program. It is also, by the City’s own description, limited: the goal is not to eliminate mosquitoes but to reduce the big waves that emerge after major rain, and it explicitly does not reduce the adult mosquitoes that fly in from temporary water in the open fields surrounding the city.

Two things follow from that. First, some of your mosquitoes really did fly in from a slough eight kilometres away, and there is nothing you can do about those. Second — and this is the part homeowners keep missing — the water on your lot is not on anyone’s treatment route. Nobody is coming to dump your rain barrel. In the surrounding communities the situation is even simpler: municipal mosquito control across the capital region was largely wound down decades ago. Your property is your program.

The Five-Day Clock

Aedes vexans is the workhorse of Edmonton’s misery. It is the species that makes up the majority of our summer mosquito population, it specializes in stealthy bites on large mammals, and it is most active at dawn and dusk. It lays eggs in dry or damp low-lying ground, and those eggs hatch in summer once water temperature climbs past 10°C. From there, development can be complete in about five days, and the adults travel a long way.

Five days is the number to hold in your head, because it reframes the job. You do not need your property to be permanently bone dry. You need no single container to hold water for a week. A bucket dumped every Saturday produces nothing. The same bucket ignored from Canada Day to the August long weekend produces several generations.

Start With The Eavestroughs

Eavestroughs are the most overlooked mosquito habitat on an Alberta property, and it is not close. The City of Edmonton’s own advice to homeowners starts with keeping yards and eavestroughs clean. Here is why they are so good at it: a trough clogged with leaves, spruce needles and shingle granules stops draining, but it does not stop collecting. What is left is a long, shallow, sun-warmed, sheltered pool full of decomposing organic matter — larvae food — with no fish, no current and no predators. It is a nursery with a roof over it.

It is also invisible. Nobody inspects their eavestroughs in July. You will happily dump a wading pool you can see from the kitchen window while three metres of standing water sits above your front door for the entire summer.

Check them from a stable ladder, or from the ground with a phone camera on a pole. What you are looking for is water that is not moving, and the tell is often visible from the ground: sagging sections, plants growing in the trough, staining on the fascia, or water that pours over the front edge in a rainstorm instead of running to the downspout.

The Standing-Water Walk: What To Check

Do this once, slowly, with a notepad, and then again after every heavy rain. You are looking for anything that holds water for more than about five days.

• Eavestroughs and downspout ends. The big one. Clear the debris, confirm water actually reaches the downspout, and make sure the downspout extension isn’t discharging into a low spot that stays wet.
• Rain barrels. A rain barrel is a purpose-built mosquito factory unless it is screened. The City’s advice is explicit: cover rain barrels with a screen to keep egg-laying species out.
• Bird baths and ornamental ponds. Not banned — just change the water frequently, so no generation gets its five days.
• Buckets, wheelbarrows, recycling bins, tarps and toys. Store pails, buckets and equipment so they cannot collect rainwater and organic material. A tarp over the woodpile with a sag in it is a pond.
• Wading pools and pool covers. Turn wading pools over after use rather than leaving them to sit.
• Old tires. A tire is the classic case: it holds water, it is dark, it warms up, and it never dries out.
• Plant saucers and planters. The saucer under the deck planter is small, invisible and re-fills every time you water.
• Low spots and window wells. If a low spot in the yard is still wet a week after a storm, it is both a mosquito site and a drainage message about your grading.
• Anything flat and forgotten. A saucer on the patio table, an upturned lid, a garbage can with the lid off, the boat cover. If it holds water even briefly, something can lay eggs in it.

While you are at it, do the other half of the job: mow tall grass, weeds and underbrush, which reduces the shady resting spots that adult mosquitoes use during the day, and check that your window and door screens fit tightly and are in good repair, so the ones you did not prevent stay outside.

The Container Mosquito — And Why It Matters More

There is a second reason to care about containers specifically, and it is not comfort. Culex pipiens, the northern house mosquito, was first confirmed in the Edmonton area in 2020. It is the species primarily responsible for spreading West Nile virus — and unlike our rain-driven nuisance mosquito, its numbers are not tied to heavy rainfall. It develops in container habitats: rain barrels, bird baths, stormwater catch basins.

That is the whole point. The rainfall mosquito is weather. The West Nile mosquito is housekeeping. A wet summer is out of your hands; an unscreened rain barrel is not.

West Nile Virus In Alberta: The Honest Picture

It is worth being accurate here, because this topic attracts both panic and dismissal, and neither is right.

West Nile virus is an infection of birds that mosquitoes pick up by feeding on an infected bird and then pass to people and animals. The first evidence of it in Alberta was confirmed in July 2003, and the province states plainly that there is a risk of West Nile virus in Alberta every year. Most of that activity happens in southeastern Alberta’s grassland region, and the City of Edmonton notes that very few mosquitoes carry the virus here.

Of people who do get infected, about 1 in 5 become ill. Most experience no symptoms or mild flu-like symptoms; severe neurological illness is rare, but the risk of it rises with age. There is no human vaccine, which is why Alberta Health Services frames prevention entirely around not getting bitten. AHS also gives the timing: the risk is greatest from early July through to the first full frost — which is to say, right now.

Protecting Yourself, Not Just Your Yard

• Time it. Avoid outdoor activity at dawn and dusk, when our dominant species is most active.
• Use DEET properly. Up to 30% for adults; up to 10% for children aged 6 months to 12 years; mosquito netting rather than repellent for babies under 6 months.
• Dress for it. Loose, light-coloured clothing. In heavy-mosquito areas, high boots and heavier pants, shirts and jackets.
• Be cautious with foggers and coils. The City recommends treating mosquito coils, propane foggers and spatial repellents as a last resort — they release a cloud of insecticide that can affect other species, pets, and potentially people.
• Report real standing water. Call 311 for standing bodies of water in residential areas; crews will inspect and treat if needed.

Where This Overlaps With Your Home’s Health

Home Pros Group cleans ducts, furnaces, dryer vents and A/C coils — we are not an exterminator, and we are not going to pretend a duct cleaning has anything to do with mosquitoes. But the eavestrough conversation lands squarely in our world for one reason: the water you are chasing for mosquito reasons is the same water that wrecks indoor air. Troughs that overflow soak the ground at the foundation. Wet foundations mean damp basements. Damp basements grow mould, and mould is one of the most common indoor air quality complaints we hear in the Greater Edmonton Area. Health Canada’s guidance for controlling indoor humidity includes exactly this: clear the eavestroughs, run the outflow to the street, and slope the grade away from the building.

So walk your property this week. Clear the troughs, screen the barrel, dump the saucers, flip the wading pool. You will get bitten less in August, and your basement will thank you in October.

Mosquitoes & Standing Water: Quick Answers

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This article is general home-maintenance information, not medical or pest-control advice. Mosquito biology, local species and program details are summarized from the City of Edmonton; West Nile virus information is summarized from the Government of Alberta and Alberta Health Services; indoor humidity and eavestrough drainage guidance is from Health Canada. Mosquito activity and West Nile virus risk vary year to year and place to place. If you have health concerns, contact Health Link at 811 or your doctor. Always follow the label when using any insect repellent or pesticide.