Branched drain with exposed pipes

Site location: 
Oakland, CA
  • Goals: To reduce water use and grow fruit.
  • Site description: The plumbing from the shower is exposed in the unfinished laundry room downstairs. There is enough height to travel outside to the landscape. The yard is already planted with fruit trees, fruiting vines, and veggie beds.
  • Fixtures and output: One shower that is used for about 10 minutes per day (2.5 gallons/minute X 10 min= 25 gallons). 
  • Cost: One 1 1/2" - 2" 3-way valve- $50,  fittings-$50, pipe-$50: material total: $150

Old plumbingOld plumbingThe plumbing from the shower was exposed in this section of wall. The pipe is cast iron, it's connected with transition couplings, often called "no-hub" couplings. They can be loosened and removed with out the need to cut the pipe.

installing the 3-wayinstalling the 3-way One section of cast iron pipe was removed. The 3-way valve is inserted in this section before the shower drain connects to the sewerline. In this picture the bands on the right are tightened and the band on the upper left is positioned but loosened in order to get the measurement of the pipe needed to connect the valve.

Labeled 3-way valveLabeled 3-way valveAfter the valve is connected with the couplings, it enables the shower water to either go to the sewer (the pipe going into the floor), or outside through the new section of pipe exiting in front of the valve. The illustration of the valve's positioning was made so the greywater users will know which way to set the handle.

ABS pipe going outABS pipe going out ABS exiting houseABS exiting house The shower water travel outside in an 1 1/2 inch ABS pipe with a continuous downward slope of 2% (1/4 inch per foot). The pipe is strapped to the wall. The hole going out is sealed with a waterproof silicon sealant from the outside to prevent moisture, air, or insects from entering the house.

Pipes are buried and slopedPipes are buried and slopedOnce outside the greywater pipe is buried, sloping downward as it travels to the plants.

double ell flow splitterdouble ell flow splitterThis system divides the water to irrigate 4 locations, one apple tree, one tree tomato, one passion fruit, and one section of climbing beans (along a trellis).

Trench into mulch basinTrench into mulch basin Home made valve boxHome made valve box

One year laterOne year later

The fruit trees have mulch basins dug around them in their drip line.

Greywater is discharged into the mulch basin inside a valve box. The basin is filled with wood chips. In this "one year later" picture the greywater is being discharged underneath the blue rectangular container in front of the tree.


trench for mulchtrench for mulch

fruiting vinesfruiting vines

The fruiting vines growing up the trellis have a mulch trench, instead of a circular basin. The trench is filled with woodchips and receives the greywater.

  • Specifications and Notes:
  • Maintenance and trouble shooting: Annual replacement of mulch.