The rainwater tank lies at the heart of every system. The first GRAF plastic underground tank was launched in 1978 and plenty has happened since then. A high standard of quality in production is an essential foundation for unique products. This ensures the good stability and precision fit of the individual components. We have even developed a new, unique production process for the Carat underground tank. GRAF manufactures first-class products: resilient, precision-fit and easy to use!