Where To Run Your Downspout Drainage Pipes
The only 90-degree angle in your downspout drainage piping should be the turn just before the pipe enters the ground, but once it's underneath the ground, you should keep any angles to 45 degrees or less so that if you need to have a professional out to unclog the line, his equipment will be able to do the job. The downspout piping should run above ground until it has crossed the uncompacted fill dirt that lies near the foundation. If you decide to bury your downspout pipe in the loose fill, keep in mind that it settles over time and the movement of the dirt can break the pipe or even turn it so that it slopes the wrong direction. If you want to bury your pipe in the foundation soil, you can, but you should pitch it pretty deeply. Let it fall one inch for every two feet of run as it crosses the fill. Once it gets across the fill, the fall can be reduced to 1/8th or ¼ inch for every foot of run.
Check the external pipe once a year or so to make sure it's still draining as the soil has moved around it. You may need to adjust it occasionally.
Once you've run the piping over or through the foundation fill dirt, you can put it in a trench that's 12-14 inches deep. If you're running down a slope (rent a builder's level to determine the amount of slope—sometimes you can't see it just by looking at it), keep the trench the same depth all the way. If your lot is level, you'll need to bury the pipe deeper the further it runs. Let the depth increase by 1/8th of an inch for every foot that the pipes run on a fairly level lot.
If you are making a trench through your beloved lawn or flower beds, you may want to have a helper drag a sheet of thin plywood alongside the ditching machine as you're digging the trench. The ditcher will throw out dirt, which you can catch on the plywood, leaving the rest of the ground neat. When the trench is done, you can replace the dirt, or, if you're using gravel, move the pile of dirt to another location, making a tidy job of the whole thing.
If you live in a place where drought is a problem either in the summer or year round, you may not want to pipe your rain water away to disperse under its own power. You may want to collect it and use it when the dry times come. An average sort of rainfall on a medium-sized roof can generate 1,500 gallons of water or more—plenty for watering gardens and lawns, washing the car in the summer, cooling the house on hot days—any number of things you may need water for. A little extra work can mean a savings of enough water to make your life more comfortable without stressing your current water supply or paying more for city water charges. People who live in the country have always collected storm water in cisterns, ponds or even rain barrels: people who live in town can use some of the same low-tech ideas for making the most of the water they get for absolutely free!
Instead of piping water to a low-lying place and allowing it to drain away, you can pipe it into a large storage container. You can use a pump to draw the water out of the container when you need it, or if it's still up the slope from where you want it, you can use a hose and let gravity do the job. If you have the space, you can create a pond for both storage and decorative purposes.
If you'd like to consult with a local plumber before installing your downspouts drainage system, don't hesitate to call a local plumber. Our plumbers are available 24/7 nationwide. Tap here to call 1-877-DRPIPES (1-877-377-4737).