Imagine going inside your RV bathroom to take shower and get refreshed. There you are swarmed by gnats!! However, small in size, these small pests can make your life hell. They can disturb you a lot and can ruin your RV experience as well as your trip and mood.

You will enter the bathroom to refresh yourself and you will come out more irritated because of the gnats in your RV bathroom. The point to focus on is where they come from. How can you get rid of them?

Gnats in your RV toilet are coming from the black tank. You have many different options available to get rid of these nasty little fellows.

Infestation of Gnats in your RV Toilet

The gnats you see in your RV toilet are more like moths or ordinary flies but slightly lighter in color. They are more fuzzy and disturbing. The actual point of concern is from where they are infesting your RV toilet. The bad news is that they are coming out of the black tank into your toilet.

Good News about Gnats

You will be surprised to read what can be good about gnats but it is true to some extent. The good news about these gnats is that they do not bite because they have no sting. They also cannot fly very far. They only fly to a few feet.

They do rest in a shady place but they are attracted to light. That is why insect killers are also very helpful to get rid of these gnats. They also get towards the toilet from the black tank when you open the toilet lid because they see the light coming down and swarm towards the toilet opening. That is why when you open the toilet lid you see lots of them coming out of the toilet. 

Another positive point about these gnats is that they do not spread diseases to humans directly. However, they come out of the black tank where there are so much harmful bacteria. They can be covered with that bacteria and if they land on your food, they can contaminate it.

Some Bad News about Gnats

These flies live and breed in organic decomposing material. The black tank and grey tank of your RV contain this organic decomposing material. The inside environment of a black tank is very suitable for the production of these gnats.

Another bad news about these gnats is that they become adult flies from an egg, just within a week. This means that there will be much more gnats in the time you will be able to kill them. The reproduction rate of these flies is very fast.

Prevention of RV Gnats

The first thing that you can do to prevent the gnats is to close your dump valves when they are not in use. You should only open the dump valves when you are doing the dumping process. Never let your waste pile up in the black tank and make a pyramid.

This happens when one of the valves is left open and the liquid waste is drained out but the solid remains there making up a pile. This will build a problem for you and will cause more gnat production inside the black tank. 

Therefore you should try to prevent this situation by checking all the valves properly and shutting them off when they are not in use. An open black tank valve will also let the bad-smelling sewer gases drift up to the toilet along with the flies and gnats.

Methods to Getting Rid of Black Tank Gnats

After closing the black tank valves properly, now is the time to do some tricks and methods to get rid of the gnats inside the black tank because they are making your black tank their new breeding ground. It is very difficult to get rid of these gnats because they lay eggs in the black tank. They lay eggs in standing water and moisture. That is why the inside environment is very suitable for them to lay eggs. 

The major objective now is to get rid of the eggs and larvae to prevent the reproduction cycle. First of all, you have to empty the tank of every type of solid or liquid waste. After that, use the following methods to get rid of gnat eggs and larvae.

Use Bleach

Many types of bleach are available in the market that can be used for the cleaning black tank of an RV. The bleach will stay in the black tank for a while to kill the eggs and larvae.

  • Take the bleach and concentrate it with water before adding it to the black tank and toilet.
  • Add ¼ cup of bleach to one gallon of water to dilute the bleach.

After that, fill the black tank to the top. It is filled to the top because this is the favorite point of gnat larvae for development. This is because the larvae get much organic material to feed on near the top of the black tank. 

However, there is not enough water or tank-treating chemicals near the top of the black tank that can kill them. After filling the tank to the top, let this bleach and water mixture sit inside the tank for many hours to let the bleach work. You have to give excess time to the bleach to reach the organic film coating formed near the top of the tank where there are eggs and larvae. 

Leaving the bleach overnight is ideal. In the next step, you have to drain all the mixed bleach and water from the black tank. You have to properly drain and rinse the bleach out of your black tank because bleach can mix with other chemicals to form chlorine gas which is a harmful gas.

Enzyme Cleaners

One of the widely used alternatives for bleach is enzyme cleaner to kill the gnats inside the black tank. Enzyme cleaner is used for killing gnats because it helps to clear the organic film layer in which the gnats lay their eggs and the larvae grow.

When this layer is destroyed, then the eggs and larvae in it are also killed. After that, you have to rinse the tank properly to get rid of them. Enzyme cleaners are also less dangerous as compared to bleach. Follow the below steps to kill the gnats with enzyme cleaners.

  • First drain out everything from the black tank.
  • Now add water and enzyme cleaner. Add more water to fill the tank to the top.
  • Now let the mixture of water and enzyme cleaner sit in the tank overnight.
  • In the morning, drain the tank and all the mixture in it.
  • Rinse the tank as many times as needed to clean it properly.
  • You may have to repeat the whole process 2-3 times to get rid of the organic film layer.

Note that you have to add hot water to the black tank. Do not use warm water because warm water provides a suitable environment for the bacteria and gnats to grow. Hot water kills them.


Why are Flies Coming Out of My RV Toilet?

Flies usually come inside the toilet from the open dump hose valve while it is connected to the sewer hose. If these valves are left open then the flies make their way from the hose to the toilet.

Sarah Michelle is a passionate writer and digital strategist interested in the evolving landscape of online content and user experience. Having closely followed the developments in digital marketing and search algorithms, Sarah brings a unique blend of insights into the marketing world and is committed to helping both creators and consumers navigate the digital realm with confidence.

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