Will Bleach Kill Grass? What to Know if You Use Recycled Water

You may be wondering will bleach kill grass if you have to use the recycled water for regular chore actions around the house. Recycled water is the wastewater used by homeowners to do other round-the-house activities. If you use the water from the laundry or the pools to water your yard and plants, you are performing a water recycling action and using the recycled water. And why would people use recycled water? It’s the draught and to save up water. 

Water Recycling Concept

Will Bleach Kill Grass
Credit by MyStarGarden

You see, more and more areas are affected by the drought. You need to be intelligent and wise in using the water. It will affect the bill, but it will also affect the water supply. You don’t want to run out of water, do you? That’s why many homeowners would use the wastewater to do things that they believe aren’t as ‘significant’ as others. They think that doing things like watering the plants, for instance, can be easily managed by using the recycled water. However, you should know that pool water or water from the laundry typically contains chlorine, which is the active substance in bleach. 

Bleach is usually used to kill microorganism, which is why people wonder whether they are doing a safe practice. Will bleach kill grass instead? What’s the point of using the wastewater if it would turn out killing their beloved garden and plants?

Bleach Killing Grass: Is It True?

So, will bleach kill grass? Yes, bleach can kill grass, but it happens when it has a high concentration. The chlorine concentration must be more than 150 parts a million (or 150 ppm) to be able to kill the grass. In the old days, it took water having more than 500 ppm of chlorine content to water a turfgrass or the football grass. And the grass died. However, it was considered a mishap within the industry. When bleach is diluted, the possibility of it killing the grass is relatively small because the concentration isn’t strong enough. 

Understanding Bleach

Bleach contains the so-called sodium hypochlorite, the liquid form of chlorine. If you see a bleach bottle and read the ingredients, you will know that it contains around 7.86% chlorine. The chlorine itself can kill grass, but the bleach itself isn’t precisely the vital source of the chlorine.

Chlorine’ attacks’ different parts of the grass. Sodium hypochlorite is a type of salt which can kill plants. The chlorine part (within the compound) would be absorbed by the roots, where it would be sent to the leaves. When you water the plants, the leaves will absorb the chlorine directly. 

Turfgrass won’t be reactive to chlorine to chlorine if you mow it regularly. The chlorine would accumulate within the grass blade’s part – the area where the grass and the blade make contact. However, if the plants are sensitive, chlorine can be dangerous because it causes a burn. The effect would be similar to overfertilization. For those sensitive plants, just enough chlorine would somewhat burn the plants, and then the plants will die. 

There is another explanation why the bleach won’t kill the grass. The chlorine within the bleach would bind soil particles so that they won’t be taken to the roots. If you pour an entire bottle of bleach within a spot, the chlorine content would be enough to be absorbed by the leaves, making the grass sick – or even kill it. But that’s not the case with recycled water having chlorine content. Aside from the fact that the numbers aren’t many, it’s most likely that you won’t be pouring it in only one spot, and that’s why it can’t kill the grass. 

What about excessive chlorine levels, anyhow? Won’t it be able to kill the grass? Yes, the extreme level can be an issue. But that’s a rare occasion. Not to mention that free chlorine tends to be unstable within the water. If you store the water for several days (before reusing it), the excess number will dissipate, making the water ‘safe’ to use. 

What about pool water? Many people say that pool water has a lot of chlorine levels. Will bleach kill grass if you use the pool water to water your lawn? It depends on how recently the chlorine has been added to the (pool) water. If the addition is recent, then yes, the water will kill the grass because the chlorine level would be high. But if the chlorine has been sitting for several days, the excess chlorine would dissipate. This is the condition where the water would usually be safe to use on the grass. 


Q: Should I use recycled water or regular water to water my lawn?

A: This decision is up to you as the homeowner. Whether you want to use the recycled water or not it’s your decision. However, you also have to bear the consequences of your actions, whatever choices you make.

Q: What’s the best way to use recycled water?

A: Let the water sit for several days. After you are done with the laundry or the pool cleaning, contain the water in a container. Let it be for several days, and then use it to water the lawn. As you pour the water, you will see a kind of sediment being left on the container. Don’t pour it onto the grass as it is the remaining bleach. 

Q: Is the recycled water safe for the grass?

A: It’s usually safe if it stays within the household perimeter. Moreover, if you let the water sit for several days, you won’t have to worry that it may harm your grass. 

Q: If I want to kill my grass, what should I use if bleach won’t kill it?

A: There are many herbicides to use – and they are relatively safer to use than bleach. 


If you want to use recycled water, you won’t have to worry about killing the grass. If you’re going to kill the grass, you can use other alternatives, such as herbicides. Now that you know the facts about whether bleach will kill grass or not, you can decide whether you still want to use recycled water.

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Jack Robert

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