How to build a patio drain

Updated April 17, 2017

Patios are perfect for barbecues, lazy summer days and a cup of tea early in the morning. They're not so great, however, when you step into a puddle of water. Prevent puddling by installing a patio drain.

Determine where the patio drain should be placed by watching the flow of water the next time in rains. If you don't want to wait for a rain shower, spray your patio with your garden hose. The stream of water will follow the natural slope of the patio. Your drain should be positioned where the water collects. You may need to remove part of your patio's surface to install the drain; if you're lucky, you can position your drain adjacent to the patio.

Decide on a final destination for the draining water. You don't want the drained water to create a puddle in your back garden. Find a gutter, gulley or natural slope that will carry the water away.

Buy a channel drain kit before you prepare the ground so you know how deep and wide to dig the trench. A channel drain kit consists of a modular, interlocking drain pipe, a drain channel and a grate to go over the channel.

Prepare the ground for the drain channel. If you're installing the drain into your patio, remove the necessary portion of the patio's surface so you can dig the trench for the channel drain. Dig a trench large enough to include a 7.5 cm (3 inch) layer of concrete on the bottom and side. The grate should sit 6 mm (1/4 inch) below the surface of the patio.

Dig a trench from the channel to the final point of your drainage system. Your channel drain kit may not reach this final point, but you still need to have it trenched out.

Spread a 7.5 cm (3 inch) layer of cement along the bottom and sides of the trench as far as your drain pipes extend. You can cement the remainder of the trench, but it is not necessary.

Lay the drain channel and drain pipes in place, connecting them to each other as you go. Work in sections, laying cement then putting in pipe, to prevent the cement from drying before you install the pipe.

Allow the cement to dry thoroughly, then install the grate over the drain channel.

Cover the drain pipe with a layer of pea gravel, then with soil. Plant grass seed or lay sod on top, if desired. If your trench extends past the drain pipe, install landscape piping or fill it with about 15 cm (6 inches) of pea gravel, then top with soil and sod.


Wear safety goggles and gloves when removing your patio surface to prevent concrete chips or debris from damaging your eyes or cutting your hands.

Things You'll Need

  • Channel drain system
  • Cement mix
  • Pea gravel
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About the Author

Annie Mueller is a professional writer and blogger. Since 2003 she has written extensively on small business, finances, parenting, education and personal growth, and has been published on Financial Edge and many other websites. Mueller attended Missouri Baptist College and earned her Bachelor of Arts, summa cum laude, in English from Mississippi State University.