Disposing of your aquarium’s dirty water is a normal part of regular aquarium maintenance. Although it may seem like a simple task, there’re some essential things to keep in mind to ensure that you’re doing it as safely and effectively as possible. We’ll go over some tips on how to dispose of your aquarium’s water properly.

You will often need to dispose of your aquarium’s water for a variety of reasons. The most common reason is simply to do your weekly partial water change.

Over time, your tank’s water becomes polluted with waste and chemicals, which is why it’s important to change the water regularly to keep the water clean and healthy for your fish.

Another reason why people need to dispose of their tank’s water is if they’re moving their fish to a new tank. In this case, you’ll need to transport some of the old tank water along with the fish to help them acclimate to their new environment.

How To Dispose Of Dirty Fish Tank Water?

When it comes to disposing of saltwater, you can’t get rid of it just like you do with your freshwater aquarium. The main reason being is that salt can actually harm your plant’s life.

If you need to get rid of the saltwater in your tank, then you can use them on weeds in your garden. You can use this water to kill them, as the salt will damage the weed’s roots, so they will eventually die.

It’s important to note that you need to be careful not to pour this saltwater into your plants and flowers.

Where To Dump Fish Tank Water?

If you’re only doing a partial water change, then you can simply pour the water down the drain. However, for disposing of a large amount of water, you’ll have to follow some other steps.

The two most common options are to:

  • Pour the water through the drain
  • Water your garden and plants with the water

Can You Pour Aquarium Water Down The Drain?

In short, yes. It’s ok to pour aquarium water down the drain, although there are a few things you need to keep in mind.

Pour Small Amounts Of Water At Once
It’s recommended to only pour small amounts of water down the drain at a time. Pouring too much water at once may overwhelm your septic system or sewage treatment plant.

  • Don’t Pour Water With Fish.
  • Never pour your tank’s water down the drain if it contains fish, as fish can escape into the wild and spread disease.
  • Don’t Pour Water With Dead Fish.

Again, you shouldn’t pour aquarium water down the drain if it contains dead fish. Dead fish can pollute the water and could even spread disease.

So, if you’re disposing of a small amount of water that doesn’t have any chemicals or fish, you can pour it down the drain. On the other hand, if you’re disposing of a large amount of water, you should follow one of the other methods we’ve mentioned.

Can I Water My Garden With Fish Tank Water?

Yes, but only freshwater. In fact, this is the preferable method, as it doesn’t require any special equipment or chemicals.

You can do this by simply pouring the water onto your plants and garden. The nutrients in the water will actually help your plants to grow.

Although be sure not to pour too much water at once, because the roots of your plants could be flooded and damaged.

Are There Benefits Of Using Aquarium Freshwater For Your Garden Plants?

The freshwater from your fish tank can be used for your garden plants and flowers, as the water contains nutrients that can help the plants to grow. The harmful nutrients for your fish are actually very good for the plants.


  • Nitrates – Promotes better plant growth
  • Ammonia – helps plants to produce more chlorophyll
  • Phosphates – Provides more energy to plants
  • Potassium – helps plants create stronger cells
  • Magnesium – promotes plant chlorophyll
  • Sulfates – gives your plants protein
  • Calcium – helps plants to create new cells

The above nutrients are essential for the growth of plants, and the good news is that your tank’s old freshwater contains just the right amount of each one.

How Often Can I Water My Plants With Aquarium Freshwater?
You can water your garden plants with your tanks old tank’s water every week or two. This will give your plants a good amount of nutrition to grow. Just make sure not to overdo it, as too much water may end up damaging the roots of your plants.


Many aquarists will simply dispose of their old tank’s water by simply dumping the water into the drainage system (more so if it’s saltwater).

However, there’re some other useful ways you can get rid of your tank’s water without harming the environment. If it’s freshwater, then you can use it as a fertilizer for your plants or as a medium to grow algae, brine shrimp, and other aquatic creatures.

There may be other ways you can think of for disposing of your aquarium’s old water. But remember to take into consideration the safety of the environment and your community.