A reed bed is gravel-filled pond with reeds growing on the surface. The gravel helps filter out impurities while the natural working of the reeds oxygenates and freshens the water. Reed beds are used as filtration for water systems, including sewage. In America, using a reed bed as a septic system violates most urban building codes. However, you can still use a reed bed to clean your grey water such as bath and sink runoff.
Choose the dimensions of your reed bed. In general, you will need a surface area of two square meters per person. Select a location for your reed bed that will accommodate these dimensions.
Dig your reed bed do a depth of a six inches on one end and 12 on the other. Keep a level, steady slope from one end to the other to facilitate drainage.
Mix equal parts dirt from your excavation, pebble gravel and river rock in your wheelbarrow. Pour in water and stir until the mixture is about the consistency of mortar.
Scoop the mixture to the edge of your excavation. Mold it into a 6-inch berm surrounding the hole, for a total depth of 12 to 18 inches. Allow to dry.
Have a professional plumber rig your house to capture your grey water and flow it out of your home at a point near the reed bed.
Dig a trench deep enough to accommodate your outflow pipe running from where the grey water exits your home to the shallow end of your reed bed. Dig a tunnel beneath the berm rather than cutting through it.
Choose, locate and install your water storage tank. Dig a trench from the bottom of the deep end of your reed bed to the intake for your water storage tank.
Install the plumbing that connects your water systems to the reed bed. If you don't know how to do this yourself, have a plumber or contractor do it for you. Mistakes at this stage can mean serious trouble.
Fill in the trenches, replacing any sod you had to remove to dig them.
Cut holes in your pond liner to accommodate the inflow and outflow pipes.
Install the pond liner in your excavation, positioning the holes over your plumbing.
Fill the excavation to a depth of 3 inches with pebble gravel.
Fill the excavation to the top with pea gravel.
Fill the reed bed with water. You can use your hose to start or wait for it to fill with grey water from your house.
Plant your reeds in the gravel bed.
Add any decorative touches you desire, such as siding for the berm or flowering plants in the bed itself.
Expect the reed bed to smell a little off for the first year as the reeds establish a colony of the bacteria that will ultimately clean your water.