The invention relates to a double-layered compacted solid water-purification product, comprising at least one first layer and at least one second layer, characterised in that the first layer comprises at least one flocculating system and at least one dispersion system, the second layer comprises at least one disinfectant which liberates free chlorine on contact with water and at least one excipient for the disinfectant, whereby said excipient releases the disinfectant into the water at a controlled rate such that the combination of excipient and disinfectant releases 0.1 to 100 mg/l of free chlorine per hour. The invention further relates to the method for production of such a product.