Is Old Swimming Pool Water Safe for Watering Plants?

The question of whether to use old swimming pool water for gardening is a common one, especially when no chlorine has been added for years. This article explores the potential concerns and provides advice on how to ensure the water is safe to use in your garden.

Understanding the Risks and Benefits

The primary concern with using swimming pool water for watering plants is the presence of various chemicals and potential contaminants that might harm your plants. While chlorine dissipates quickly, other substances like algaecides, salt, and minerals can accumulate over time. This can result in adverse effects on plant health and soil quality.

Chemical Composition and Contaminants

Swimming pool water typically contains several chemicals, including:

Algaecides: These chemicals can take weeks to months to fully degrade. If algae are present in your pool water, it suggests that the algaecide may not be fully effective, which could pose a risk to your plants. Chlorine: Chlorine, if present, will dissipate within a day under sunny conditions. High chlorine levels can still cause damage, but it is less of a concern over time. Salt (from saltwater pools): If your pool uses a saltwater generator, the water may contain salt. Salt concentration is usually one-tenth that of sea water, which is generally tolerable for most plants but should be tested before use, especially for sensitive species. Total Dissolved Solids (TDS): High TDS levels, especially above 1000ppm, can be harmful to plants, as they contain minerals and other solids that can alter soil chemistry.

Testing for Safety

To ensure the water is safe for use in your garden, it is advisable to test the water for various parameters. Key tests to consider include:

Alkalinity and pH levels: Most plants prefer a neutral pH level of around 7, but some prefer slightly acidic or alkaline conditions. Testing the pH of the pool water can help you make adjustments if necessary. Chlorine residue: High chlorine levels can be harmful, so testing for chlorine content is important. Total Dissolved Solids (TDS): This will give you an idea of the mineral content in the water.

If the TDS exceeds 1000 ppm, or if the water contains high levels of other anti-plant chemicals, it's best to use water from other sources. However, if the TDS is acceptable and the water is otherwise safe, you can dilute the pool water with fresh water to make it suitable for plant use.

Alternative Solutions

If you're hesitant to use the pool water directly, there are alternative solutions to ensure your plants receive appropriate hydration:

Test the water: Check the water's chemical composition and pH level before applying it to your plants. Dilute the pool water: Mix the pool water with fresh water to reduce the concentration of any harmful chemicals. Use rainwater or tap water: These are safer and often more readily available sources of water for your plants.

Conclusion

While old swimming pool water can be a valuable resource for your garden, it's important to test and properly treat the water to ensure its safety for your plants. By following the steps outlined in this article, you can make an informed decision about whether to use pool water for your garden and how to do so safely.