Abstract: A storage-stable, stop-leak formulation contains a ground plant root material, an alkaline metal salt of a C1-C3 carboxylic acid and water. The formulation may further include corrosion inhibitors, biocides, lubricating agents, dyes and the like. Typically, the stop-leak formulation includes 1-50 parts by weight of the root powder, 1-15% by weight of the salt and 120-180 parts by weight of water. Preferably the root powder is ginger root powder and the salt is potassium acetate.