Siphonic and Gravity Rainwater Drainage Systems Welcome to Rwp-Clearflow, leaders in rainwater roof drainage systems. As rainwater intensities increase it is vital that your rainwater drainage system is correctly designed with the capacity to protect your building and contents. Siphonic rainwater drainage systems move more water, through smaller pipes, with less ground work than conventional gravity fed systems. It's that simple! We can provide the products and the expertise to design and install the optimum drainage solution for your new build or refurbishment project.
