Plumbing For Greywater

plumbing for greywater
october 2015
christina bertea
~union trained journeywoman plumber (1978)
~plumbing contractor (1996) ~greywater action
[email protected]

plumbing for greywater
• basic parts of a drainage system • identifying the correct drain pipe • where to cut in the three way valve • how to cut the pipe to install the three way valve • how to connect the three way valve • new greywater piping from the three way valve to the
garden

drainage system
• gathers together wastewater from all fixtures in the building
• a “fixture” is a toilet, sink, tub, shower, washing machine... where freshwater enters and wastewater flows away
• size of drain piping is determined by volume of wastewater flowing through it
• 1/4” per foot “slope” or “grade” for optimal gravity flow and removal of solids
• a single large drain carries wastewater out of the building to join the sewer and flow by gravity to the sewage treatment plant, or to a private septic system

basic parts of a drainage system

• fixture • trap • trap arm • vent • drain • sewer

GREYWATER DRAINText

BLACKWATER DRAIN

traps
• required at each fixture
• hold water creating a “water seal”
• prevent sewer gases and vermin from entering building

vents
• every trap must have a vent
• prevent siphoning of trap seal
• extend through roof to outside air

(sink)
trap

• allow air to equalize pressure in drain/sewer system

• prevent explosive build up of gases

vent up to roof

sanitary

(toilet)

greywater

black water

drains: sized according to fixture/s they serve
• toilets: 3” or 4” drain pipe • bathroom sinks: 1-1/4” or 1-1/2” trap and drain • kitchen sinks/laundry sinks: by code 1-1/2” trap, 2” drain* • bathtubs: 1-1/2” trap, 2” horizontal drain* • showers: by code 2” trap and drain* • washing machines: 2” trap and drain • * older buildings may have undersized drains for these fixtures

DWV copper galvanized steel
leaded cast iron drain materials: in older buildings often main/toilet drain will be
cast iron, smaller drains will be copper, galvanized steel, or ABS

drain materials
and method of connection
2” ABS plastic
glued joints
2” no hub cast iron
joined with no hub bands

(leaded cast iron not shown)
1-1/2” copper DWV
soldered joints
1-1/2” galvanized steel
threaded
joints with Durham fittings

copper pipe

WATER DWV

DWV (“drain waste & vent”) copper drain lines have yellow stripes copper water tubing has red, green, or blue stripes and thicker walls
careful not to cut a water line!