I have a dry well to prevent my yard and studio/office from flooding. It has a rim of bricks, which rise above the ground a little to stop too much garden waste entering the well (I guess). I want to cut channels into the bricks to improve water flow: it seems that the top of the rim is almost level with the top of the step into the studio. But, I also want to prevent mosquitos from breeding in it.

photo of dry well showing edge/rim with inadequate inlet channels Photo of dry well showing edge/rim with inadequate inlet channels.

photo looking down into dry well, showing the pump and float and outlet pipe Photo looking down into dry well, showing the pump and float and outlet pipe. The rim is made of newer bricks; presumably it was added recently to keep out garden waste.

photo of a nearby building entrance with a high water mark almost at the point where it would overflow indoors Photo of a nearby building entrance with a high water mark almost at the point where it would overflow indoors.

How can I increase water flow into the dry well while also keeping mosquitos out?

I could make the channels wide and install a mesh, but I'm hoping for something simpler. Mosquito nets need to be finer than 1.2mm, but I wonder if these can be a little wider because they will be deep grooves, not a thin mesh? So like, how narrow do other gaps around the house have to be to prevent mosquitos, e.g. gaps around doors? I plan to use a circular saw which I think will be wider than 1.2mm.

As visible in the photos above, the well currently has a cover that definitely won't keep mosquitos out. I'll be replacing that for sure.

  • 3
    it should be Mosquito net size
    – Traveler
    Oct 14, 2022 at 1:40
  • 1
    There are also insecticides made for open water places(wells, tanks, ponds) for mosquitoes.
    – crip659
    Oct 14, 2022 at 10:48

1 Answer 1


I'm a bit confused about the layout of your dry well that it has a rim of brick that you want to modify to allow more water but no mosquitos through, but aren't worried about them just flying into the opening. In any case...

According to this site:

  1. Treat Water Features

Here are some easy ways to steer mosquitoes away from water features like fountains and pools:

  • Run fountains and other water features regularly so that the water keeps moving
  • Regularly clean water features
  • Grow mosquito-repelling plants, such as rosemary, lavender, citronella, catnip, and mint, close to water features
  • Apply solutions of larvicide to interrupt the breeding cycle
  • Sprinkle the water with cinnamon
  • Add essential oils to the water
  • Add mosquito-eating fish

Some points will require regular maintenance after every rain when there's water sitting in the dry well and may be impractical. However, decorating around the top with the plants near the "water feature" will be an ongoing solution that requires a minimum of maintenance on your part.

Following some of these suggestions should help prevent the mosquitos from getting into the well and breeding in the first place. Additionally, if you plant mint, it tends to spread, so you could transplant some to other locations around your yard and, possibly, end up with an entirely mosquito free yard!

  • Good advice. Other Q&As mention putting a coil of copper wire to the well. But might that cause corrosion in the pump? (I'll add a photo and details of the pump) Also, I've heard that a tiny amount of (food) oil can create a film to stop mozzies, but I'm concerned about pollution since this gets pumped into a storm water drain. But, the pump doesn't empty the well below its intake so hopefully that's not a problem.
    – z0r
    Oct 15, 2022 at 2:03
  • As for the top opening: yes you're right, and I'll cover it with a grate and mesh. So I have two coupled concerns: keeping mozzies out, and letting more water in, while not requiring too-frequent cleaning. Cleaning the mesh and adding a tablespoon of oil once per quarter and after heavy rain sounds manageable.
    – z0r
    Oct 15, 2022 at 2:08
  • I'm starting to think I should completely remove a couple of bricks from the rim and put a grille and fine mesh there. Water channels narrow enough to keep mosquitos out would probably have too little flow.
    – z0r
    Oct 15, 2022 at 3:36

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