My house has 6 dry wells for collecting waste water from bathroom and kitchen.

I'm worried that it could become a breeding ground for Mosquitoes , Bacteria, virus and foul smell.

Are there any guidelines on how to treat the water so I can prevent harmful effects ( Malaria,Dengue,Legionella etc..)

As far as I can think

  • Have a breathing pipe on top of all all the dry wells and cover it with mosquito net so mosquitoes can't enter or exit and there will be some aeration as well

  • Pour cup of disinfectant mixed with water in each dry well.

Update: -

I'm noticing that smell coming out of the drainage pit and entering the home sometimes.

I assume it could be toxic.

Is there anything I can do to stop the toxic gas from getting formed ?


Is there anything I can do to stop the gas from entering the home or dealing the gas once we notice it ?

I have heard that Carbon monoxide is odourless and it could cause issues.

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There is clothes line for drying which runs parallel to the pits.

Would the gas or something that comes from the pit affect the clothes

I mean would it act as carrier to affect the health ?


Are there any plants that I can plant around the drainage pit which can absorb the Carbon monoxide and other drainage gas ?

  • 1
    Environmental friendly would be Salt. Buy a bag of pool salt and put few cups in the well. Most creature do not like salt water. Mosquitos do not like it.
    – Traveler
    Commented Aug 20, 2022 at 7:18
  • 2
    Isn't a septic system the traditional solution to this issue? Also, if you have standing water in these dry wells, doesn't that mean they are not draining properly?
    – Armand
    Commented Aug 20, 2022 at 23:06
  • 1
    As far as mosquitos go, I believe there is a natural product (Bt?) that you can put into small standing water areas that will kill mosquito larvae. "New microbial larvicide formulations that can last for one to three months across different types of habitats have been field-tested"; "Aside from being harmful to aquatic insects, neither larvicide is toxic to other animals, pets, or people. They will not harm plants either."
    – Armand
    Commented Aug 20, 2022 at 23:10
  • 2
    Have you tried to contact the health department for the area where you live. I have to imagine that if they allow this type of waste water well there are rules that have to be followed and they know what risks you may face.
    – RMDman
    Commented Oct 3, 2022 at 1:37
  • 2
    Are these dry wells or are they actually a septic system? If you're draining household water into them, they're more likely a septic system and those work and should be treated entirely differently than a dry well. It might be a difference in terminology between your part of the world and mine, so I've included links describing the terms so we can have consistent usage.
    – FreeMan
    Commented Oct 4, 2022 at 13:06

2 Answers 2


Firstly let me assume you that the dry wells do not contain septic water that is from toilet flushing. Drywells are for "Gray water" from sinks or tubs, and rain water that collects. Carbon monoxide is a byproduct of combustion, and would not be an issue. Methane is produced from decaying sewage, and is not odorless. The smell resembles someone passing gas. Your dry will should not be producing this smell. You can shock the drywells with a cup of bleach in each one, If there is standing water, That should take care of any micro organisms in it. Please contact a professional to inspect your septic system to make certain that it is not leaking into your groundwater, And collecting in the dry Wells.

  • 1
    Methane is odourless. That is why methane for fuel has methyl mercaptan added to it, so you can smell a leak. The smell of sewage is from more complex molecules.
    – Chenmunka
    Commented Oct 7, 2022 at 8:37

If you believe the smell is entering the home from the pipes and not through an open window / opening in the structure, then you may want to check two things:

  1. There are p-traps on all lines running to the dry well from the house as these are a simple method to block gases from coming back in
  2. If there are p-traps on all, then ensure you run water often enough in each of them to not let the p-trap dry out which would compromise it's effectiveness
  • Thanks for the answer , There are some fixtures that I don't have P-Trap. I will sure install the traps for those.As of now I believe the smell is coming through my window to the hall. The air vent is just 1 feet from the ground.
    – Amogam
    Commented Oct 8, 2022 at 19:06

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