The Importance of Source Water for Aquaponics

Growing aquaponically means that you depend heavily on water, and in building your own aquaponics system, the source water is one crucial consideration that you need to consider. It is because water is the lifeblood of an aquaponics system. Through water, all the essential nutrients are transported to the plants, and it is also the medium through whichfish receive oxygen. However, not all water is equal; water can have different oxygen levels, be treated with chemicals, or be contaminated. 

That is why aquaponics growers need to pay close attention to the quality of water being put in the system because it is also used to accommodate fish. This blog discusses the different water sources for aquaponics, the best source water, and what to do with treated source water. 

Sources of Aquaponic Water

The source water you will use in your aquaponics system will have a significant impact on the water quality of your system. As a general rule, it is recommended to test water for chemicals and contaminants before using it in your system. Once your system is up and running, only small amounts of water are added to your system to make up for the water lost through evaporation and transpiration. Below are some of the common water sources for aquaponics systems.

Rainwater as Aquaponics Source Water


The collected rainwater usually has a neutral pH and a very low concentration of both types of hardness (KH and GH). Rainwater has almost zero salinity, which is excellent for aquaponics systems because it helps avoid long-term salinity buildups. However, in areas affected by acid rain, their rainwater has acidic pH, so it is recommended to buffer the collected rainwater to increase the KH.  

Rainwater is the best choice of water to use in your aquaponics system. It is fresh, pure, and potable water. Rainwater is also free, and collecting it will help reduce the cost of running your aquaponics system, making it more sustainable. 


Well Water in Aquaponics

Wells and Springs

The quality of water taken from wells or springs will largely depend on the materials and bedrock. If the bedrock is limestone, then the water will probably have relatively high concentrations of hardness, which may impact the pH of the water. So it is essential to test and check for pH as layers or rocks tend to dissolve minerals like calcium, making it harder to adjust the pH. 

River Water  Source for Aquaponics

Rivers, Creeks, Streams, Ponds, and Lakes

Due to being open and many creatures living, including different fish species, these water sources have higher contaminants and nutrients. Using water from these sources may lead to nutrient overloading, so filtering and treatment may be needed to prepare the water for aquaponics use. 

Municipal Water Source for Aquaponics

Municipal or Tap Water

Most aquaponics growers use municipal water for their systems. However, water from municipal supplies is often treated with different chemicals to remove pathogens. The most common chemicals used for treating municipal water are chlorine and chloramines. These chemicals are toxic to fish and bacteria, so it is essential to dechlorinate the water before using it in your system. 

The simplest method of dechlorinating the water before use is to store water for at least 48 hours to allow all the chlorine to dissipate into the atmosphere. Chloramines are more stable and do not off-gas easily. So if your municipality uses chloramines, it is necessary to use chemical treatments to clean the water. 

An easy and safe way of removing chloramines is vitamin C. 100 milligrams of ascorbic acid (Vitamin C) can treat ten gallons of water. Adding vitamin C to your water will neutralize the chlorine and most of the chloramine. Another option of removing harmful compounds is using high-grade or medical-grade activated carbon filters. 

Things to Consider when Sourcing Aquaponic Water

Every aquaponics system is unique, and so are the environmental and water conditions of each location. The treatment of groundwater differs from each area depending on contaminants in the water. Here are the main things you need to consider in choosing source water for your aquaponics system.


pH or the acidity of the water affects the availability of the nutrients in your system, so you will need to adjust the pH according to your system’s needs. There are simple methods of adjusting pH in aquaponics and for an in-depth discussion, read our blog on the importance of pH in aquaponics

Chlorine and Chloramines

Chlorine or chloramines are added to almost all municipal water to remove pathogens. When chlorine and ammonia are combined and added to the water, chloramines are formed. Chlorine and chloramine are dangerous to nitrifying bacteria, which is the foundation of an aquaponics system. So it is essential to test the water before adding it to your system and remove the chlorine and chloramine. 


The hardness of source water is essential because it affects the buffering capacity of aquaponics systems. Hardness is a measure of dissolved calcium levels and magnesium in the water. The harder the water, means more dissolved minerals are in it. 

There are two types of hardness: general hardness (GH) and carbonate hardness (KH). General hardness is the measure of positive ions. Carbonate hardness is also known as alkalinity, which is the measure of the buffering capacity of water. Carbonate hardness in the water impacts the pH level because KH acts as a buffer to the lowering of pH.

Hard water can be a valuable source of micronutrients for aquaponics and does not affect the living components. Well, water is typically hard because of the presence of natural minerals and carbonates. Municipal water has lower hardness and is more susceptible to pH swings. 


Aquaponics Water Test Kit

Water Testing

To maintain the good water quality of your aquaponics system, it is recommended to perform water tests before using it in your system and perform maintenance tests once a week to ensure all the parameters are within the optimum levels. 

Mature and established aquaponics systems will have consistent water chemistry and don’t need to be tested often. In these systems, water testing is only required if a problem is suspected. It is also recommended that every aquaponics grower have access to simple water tests so that they can quickly be acted upon when a suspected problem is present. You can easily purchase color-coded water test kits that include ammonia, pH nitrite, and nitrate.

Treating Water in Response to Water Test Results

Discovering a high ammonia level on unusual pH level reading may make you feel panicked and stressed, but water quality treatments need a calm and steady hand. Panicking and treating the problem too aggressively to make a drastic change will only shock the system and increase fish and plant loss. Treatment should be done gradually to ensure that adjustments occur slowly and are long lasting. Here are some tips on treating or adjusting source water for aquaponics systems.

  • The critical thing about adjusting water parameters in aquaponics systems is to make gradual changes. Doing too much can cause undesirable and irreversible damage to your aquaponics system.
  • Perform water addition and adjustments outside the system. This will help prevent unintentional changes that could be harmful to the living components in the system. This is important if your tank has low water hardness and is susceptible to quick changes.
  • Never replace more than 10 percent of the water in your system without testing and removing the chlorine or chlorine first.
  • Add source water to the grow bed area and not directly into the fish tank. Doing this will help lower the chances of fatal swings.
  • Water should be tested and treated before use in an aquaponics system.


Your source water choice is one of the essential things you must consider when starting a new aquaponics system or adding water into your existing system. Carefully source your aquaponics water, and always bear in mind to check and test the water for chemicals and contaminants before using it in your system. Thank you for reading our blog, subscribe to our mailing list for more aquaponics updates.

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