Ideas
Click on Illustration to learn more about the potential water savings from
recycling graywater.
Branched Drain System
A branched drain system is used to collect graywater from showers and tubs. The threeway diverter valve that allows you to send water to the sewer or the garden is installed on
the drain pipe in the crawl space under the house. If the crawl space is difficult to access,
a switch is installed in the bathroom that connects to a motor that opens and closes the
valve. A branched system requires a permit and is usually installed by a professional.
Branched drain systems rely on gravity to deliver water so you must have a consistent
flow downhill from your fixtures to your plants – at least a 1/4 inch drop per foot.
Pumped System
Add a surge tank and sump pump outside your home and you can irrigate anywhere in your
garden, uphill or down. A family of four that collects graywater from its clothes washer,
showers, baths and bathroom sinks can save up to 60,000 gallons a year for irrigation.
In an existing home, obtain a building permit and hire a professional to install threeway diverter valves on the drain pipes from bathroom sinks and tubs. If you are building
a new home, work with the contractor to configure the plumbing so that blackwater
from toilets and the kitchen sink is directed into one sewer line and graywater from
laundry, baths, showers and bathroom faucets is directed into a separate pipe. A threeway diverter valve will allow you to direct the graywater to the surge tank or the sewer,
and the surge tank will have an overflow line to the sewer as well. The surge tank should
be at least 55 gallons and outfitted with a submersible, dirty water pump. Energy use is
minimal as the pump operates only a few minutes a day.
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