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Is treating water with lime allowed in organic production?

Answer: It is important to note that any water used in organic operations must meet standards and regulations first set forth by the Environmental Protection Agency’s (EPA) Safe Drinking Water Act. The use of lime as a water treatment in organic operations depends on the use of the water, i.e., crop production, postharvest handling, or livestock watering, as well as the type of lime used.Lime is one of the most common methods for softening hard water. In addition, it is used to adjust the pH of water, remove solid particles to lessen the turbidity of water, remove pathogens, and remove other impurities such as silica. Depending on the type of water treatment and filtration system, different types of lime can be used. Some systems call for lime-soda ash treatment (slake lime), and dolomitic lime is often recommended as well. However, these materials can jeopardize organic certification for your farm, depending on how they are used. If organic certification is one of your goals, it is best to always contact a certifying agent and ask if a proposed water treatment would meet certification standards.One way to evaluate this prior to checking with a certifier is to search the Organic Materials Review Institute’s (OMRI) lists of products and materials used in organic production. OMRI provides third-party verification of organic input materials. Also refer to Subpart G ? The National List of Allowed and Prohibited Substances ? under the National Organic Program. As you will see, the use of a substance is dependent upon how it is being used in the operation.To learn more about organic certification and related topics, check out the Organic Farming section of the ATTRA website.