Is Well Water Okay for Aquariums?

All aquarium fish adapt to the water conditions they face in the wild. These can vary wildly. Some species come from stable water with specific parameters, while others can live in a range of conditions. However, well water varies considerably, and may not work for aquarium fish. The safety of well water for aquarium fish depends on the fish and the well.

  1. Possible Natural Hazards

    • Throughout the United States and most of Europe, municipal water has to meet certain safety standards. However, in a private well, you have to make sure your water is safe for human consumption yourself, and that's the first step to making sure it is safe for fish. Well water should be tested for several natural hazards including bacteria, radionucleotides like radon and uranium, fluorides, and nitrate and nitrite.

    Possible Artificial Pollution

    • Well water sometimes contains artificial contaminants. Check for these for your own health before worrying about your fish. Fertilizers and pesticides can contaminate well water, as can heavy metals such as lead and copper. Nitrites can occur naturally or from agricultural waste. Most of these contaminants can enter groundwater through either industrial or agricultural applications. Mining and farming often contaminant groundwater.

    Health Testing

    • The Environmental Protection Agency recommends that you test well water yearly to make sure it is safe for human consumption. The EPA's recommendation is that you send a sample off to a certified laboratory. However, these tests are geared toward testing and certification for human safety. Water safe for human consumption may not work for aquarium fish, but this makes a great starting point. If water is not fit for human consumption, it will kill the vast majority of aquarium fish.

    Aquarium Testing

    • When you've established that the water is safe for human consumption, additional tests make sure it's safe for aquarium fish. Use aquarium test kits to test for pH, phosphate levels, hardness and nitrogen compounds. For nitrogen compounds, look at ammonia, nitrite and nitrate levels. Compare these values with the ideal parameters for your species.Many unsavory levels can be corrected if necessary, but it must be done before you add fish to the water. In saltwater aquariums, you likely will need to take the extra step of running the water through a reverse osmosis unit, since marine salt mixes are designed to work with exceptionally pure water. As an alternative, use distilled water or water designed specifically for aquariums instead of your well water.