Can i kill gnats with whie vingar by pouring it down my sink and shower?

You may be experiencing drain flies. A common problem in restaurants especially with floor drains. Not knowing your accomadations if it's a basement apartment or even your kitchen sink they could be coming from the P-trap under the sink. Possible solution are to treat the drains with disinfectant liquid lysol or iodine. Bleach doesn't seem to work as well. How about fruits? maybe something forgotten in a cupboard. Hope this helps.

Have you located where the gnats are coming from?

Step 1 - Identify the source and remove it. (If coming from a drain pour a small amount of bleach down each drain.)
Step 2 - Make a homemade trap to catch the existing gnats. You can do this by pouring some apple cider vinegar into a mason jar or small container. Place plastic wrap over the top and poke a few small holes in it.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/zachary_77e7f3432fcae581

close up the house and place a bug dead cannister in the rooms
while they are working take a long walk or go shopping
follow the instruction properly as the gas produced will kill everything in the building

6 Ways to Instantly Get Rid of Gnats at Home - Organic Lesson

www.organiclesson.com/6-ways-to-instantly-get-rid-of-gnats-at-home/
Preventing Gnats in the Future. Clean Up Dirty Dishes. Make sure there aren't any dirty dishes lying around in the sink. Cover & Get Rid of Trash bags. Make sure your trash cans are well covered. Get Rid of Damp areas. Change pot soil.

Not really, the Gnats will just avoid them. If you have Gnats, hopefully your plumbing has been installed properly. The best thing to due is have a licensed plumber come over and snake the drain. This will prevent them from coming up from the sewer.

http://www.wikihow.com/Get-Rid-of-Gnats
Try this link.

I like to use natural remedy's. here is a link for you to look over.
Natural Remedies to Spray Kill Gnats on Plants

• Clean up the living area where the gnats are hanging around. This is usually the kitchen .Take away all garbage, clean the sink disposal, and throw away any food residue.
  

• 2

  Spray the counters with a cleaner that contains bleach to discourage gnats. Dry off the counters with paper towels.
  

• • 3
  • Find out where the gnats are getting into the house. If there are cracks around windows or doors bass seal them. Fix any window or door screens.

Elimination

• 4

  Pour a cup of ammonia down your sink drains and disposal to coat the inside. Gnats inside the drains will quickly die.
  

• 5

  Mix together equal parts apple cider vinegar and dish detergent.
  

• 6

  Pour the mixture into small dishes or cups and set them out in the areas where gnats congregate. The gnats will be attracted to the sweetness of the vinegar but will get caught and die in the dish soap.
  

Prevention

• 7

  Keep trash cans covered at all times, and empty them every night.
  

• 8

  Leave your compost buckets outside. Gnats love vegetables and fruits.
  

• 9

  Avoid over watering your plants. Soggy soil attracts gnats
  

1. Get rid of their food supply.
2. Cover your trash cans.
3. homemade trap. Fill jar with viegar. Seal the lid on tightly, then poke small holes in the lid. Leave in kitchen. Gnats can fly in but can't get out.
4.Pour olive oil in kitchen sink.gnats will fly in but won't be able leave.
5. Use a professional insect spray.