Does pouring bleach into a septic system hurt the septic system?

Yes, it is bad to do so.

Remember that septic tanks work by having cells take the incoming kitchen and bathroom waste and converting that into, well, waste. In other words, the microbes are converting the by eating it.

Bleach (and other chemicals) kills the microbes. No microbes, and the septic stops decomposing the waste, and it backs up, and you get it pumped more frequently.

Now, a teaspoon of bleach isn’t going to matter. But a significant amount frequently—bad news. DOn’t do it.

Especially straight bleach. Dilute it with a TON of water.

(Septic in my back yard)

Septic system in my back yard too.

I would not pour down more than about 8 oz. You want the bacteria to work.

Does your bathtub drain have a trap? That is supposed to act like a check valve so the odor and bugs can’t get into the house.

Oooo! Have you not used that bathtub for a long time – enough time for the trap to dry out? Will that happen often like when you go on vacation?
If yes, then I can tell you about a neat system I saw in Japan. They had a thin layer of oil (vegetable oil?) floating on the water. The water could not evaporate but fresh water could flow into and under the oil.

Yes, but if you just pour a half to a full cup it won’t be a problem as long as you aren’t doing it often. People with septic use bleach in the laundry machines and other chemicals go down the drains.

You can add some septic bacteria if you’re worried.

yes it will. Many things will hurt a septic system. There is nothing more shitty than a septic system or drain field with problems.

You have flies coming up through the drain from the septic system? You may want to have a qualified plumber check to see that a P-trap is properly installed in the bathtub drain line.

You could just cover the drain with one of those rubber jar-opener things when not in use. Thy flies should die out if there’s no outlet.

You might try pouring a little alcohol down the drain, or even, perhaps, vinegar. They’re at least naturally occurring products.

I can only assume that there is a collection of waste in your pipes that is causing the flies. If the flies were in the septic tank, and managing to come up the drains, I think they would be the least of your problems – the smell of the tank being the main thing. the flies must be further up the drain nearer the house. Bicarbonate of soda (which I think in american is called baking soda) is good for clearing drains and is fine for septic tanks. I also bought a product that unblocks drains and is septic tank friendly, so you might want to try something like that. You should only use products that say they are septic tank friendly.

No bleach, that’s my main septic tank rule. Pee, poo and paper is my other rule for what you can flush down the toilet.

The old-fashioned recipe is this: pour a half cup of baking soda into the drain (as @Stinley suggests) but then follow it with a cup or a bit less of the cheap vinegar – I keep a gallon of white vinegar around for cleaning and it lasts a long time. The vinegar will make the baking soda fizz up (oxidize I guess), and that should kill the varmints, and also will polish up the inside of the pipes nearest the drain.

Ooooo!!!! I just thought of something!

I’m betting you have a wad of old hair stuck down in the drain. You’ve noticed that the sink has been draining more slowly recently but it was fast enough so you left it alone. Right?

Get one of these. Zip-It clog remover They are only ~$3.00 and work great! Watch the video before eating lunch!

Please let us know what happens.