Repel Flies With A Bag Of Water

Repel Flies With A Bag Of Water

Annoyed by the household fly? Turns out all you need to deal with that pest is a plastic bag or two.

Photo by brookage.

Reader RickyC wrote in to tell us that he recently visited a lakeside restaurant and noticed some clear plastic bags filled with water hanging from the railings. When he inquired about the bags, a waiter explained that they were used to repel flies.

Question-and-answer web site The Straight Dope gives more detail on why this trick works:

Evidently, houseflies, being highly edible and defenseless, are nervous types, and don’t like to sit still when they see something moving nearby, because it could be a predator. The water bag acts a bit like a lens—try it some time—in which the movements of people in the area are reflected. Even if the fly is too far from the action to see it directly, it can see a shifting of light and dark in the water bag, which it interprets as nearby movement, and it will fly away from the bag.

So, next time you have a fly problem, grab a few plastic bags, fill ’em up, and let us know how this trick works for you. Likewise, share how you keep unwanted insects out of your backyard—including whether or not you’ve tried this method before—in the comments.

What’s the Purpose of bags of water hanging in restaurants? [The Straight Dope]


  • It might work for the flys outside of Australia, but who are you kidding. Australian flys are more decisive than God himself.

    During summer when they stick to you now matter how much you shake and dance they immediately sit back on you.Once when I was catching the train one of them sat on me and no matter how many times I tried to make it understand i don’t like it, it just kept coming back, until I reached city and it left….may-be he had an interview or something, he was nervouse. But on the serious side, the flys in Australia, they are awefull, they just don’t get it when they are not welcome.

    • I’ve previously been given the hardware store sort as well as made my own. They’re extremely effective. The last one I put a couple of prawn heads in and over the course of a week caught SEVERAL HUNDRED flies and that’s in suburban Brisbane. It was DISGUSTING.

  • We live in the Seattle, WA. area.
    After a recommendation about the zip locks
    filled with water……..we tried it. Looks
    silly perhaps, but it WORKS! Thoughout the
    past month, and it has been warm and doors
    have been open, we have had no flies since
    hanging the bags above the doorways (2) in
    separate rooms. We are amazed & delighted.

  • Until a few days ago you could also put me in the skeptic column. We visited a local outdoor restaurant for brunch, and questioned the gallon size Ziploc bags partially filled with water and spaced about 10 feet apart. We were told they repelled flies. We’ve eaten at this place for years and flies were always a problem. I couldn’t find a fly anywhere…not on the patio cover, not on any walls, not flying around. I was convinced they had a commercial fly trap somewhere, but they didn’t. Am I still somewhat skeptical…yes. Did I enjoy a completely fly-free brunch…yes. Maybe it is an urban legend, or a coincidence, or the phase of the moon, but it sure seemed to work. Good luck.

  • My wife and I tried the bags of water and have them hung at our back sliding doors, Usually there are flys all over these doors not letting us in or out without flys coming into the house, Since the bags are up I only see 1-2 flys, I would say this works.

  • We attend a barn dance this time of the year
    every year. Everyone brings a dish to share and
    the sponsor has BBQ pork and other meats.
    Never fails as soon as the food is put out
    thousands of flies appear. Of course, considering
    it is a hay mow, in a barn, on a farm that is also a given. However, this year we found baggies half full of water with 5 pennies nailed to the walls. When we asked about them she told us about them repelling flies. WELL! IT WORKED!!!!
    We did see a few flies but not like previous years
    Amazing! I heard several philosphies of why they work but I just care they that it works. Yea!

  • I just moved to texas and have never seen so many flies. The are bigger here I think. Anyway I open the door and they all just swoop right in and its discusting and bothersome to me and my poor dogs who are constantly chomping at them 🙂 I placed 3 plastic bags on my back patio with a little water and a piece of reynolds wrap foil and I have no flies at all on my patio anymore sooo from my experimenting it seems so work, no more buzzing!!!

  • This method also works for ants inside your house. We had a huge problem with ants invading our kitchen for many months then my mother placed small ziploc bags filled with water on each of the countertops and 2 days later amazingly they were all gone. It is a great organic and animal/insect friendly way to guide them back outdoors.

  • No urban legend this…..I live across the road from a cow pasture…….need i say more?? I use the plastic water bags (small ones, and tape them to the outside of the door.) and NO MORE FLIES!

  • I read this three days ago and immediately put up some bags of water. At first thought it was working, but next day and today, flies are even landing on the bags!! Are you supposed to shut all the doors and windows after spraying the entire house for it to work? C’mon dudes, let us in on the secret??and what about the ‘pennies’? whats that about please?? huh? Damn! these flies are buggin’ me.

  • I filled plastic baggies with water and tacked them up around my back patio. It did not help the fly problem, they land and sit happily on the bags. So I’m trying the water jug remedy. Flies land on it but won’t go in it. :/ But, it’s only been an hour for the water jug test so I’ll give it more time to work.

  • I live in Texas as well. With our mild winter, the flies are horrible this year. I would come home from work and there would be 50 flies inside my sliding glass door. How are they getting in??? Arg! It was driving me crazy! So, I tried the old bag trick… half full of water, with one penny. I hung it outside the door & it worked!!!!!! I might see one or two flies… that I can live with. No more insanity like before! 🙂

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