From simple downspout extensions to complex drainage problems, we have the drainage solutions. Rain-N-Drain has the experience and equipment to put storm water problems where they belong. The proper grade, fall or slope for pipe placement is critical. Any reversals or dips in the grade will greatly reduce the life and effectiveness of the drain system. The pipe should have a continuous downhill fall over the entire lenght of the drain line. Pipe should drop 2.5 inches every 10 feet which amounts to.25 inch for every foot.