Match Supply to Demand
Ideas
Matching the amount of graywater you divert into your garden to the amount of water
your plants need is not an exact science, but the goal is to assure that all of your graywater
percolates into the soil to avoid runoff.
The state of California estimates that a load of laundry generates 15 gallons of graywater,
and that bathing generates 25 gallons of graywater per day, per person.
Estimating demand is more difficult because the water use of plants and trees changes
with the weather. It also changes as plants mature and grow. And water-efficient plants
don't need water every day. Here are a few tips to align supply and demand:
Use graywater to irrigate shade trees, fruit trees, shrubs and hedges.
Estimate your water demand based on your soil type (test your soil) and each plant's water
use, and choose the type of graywater system that will not exceed demand.
Only water plants when they need it. When they don't, divert graywater to the sewer.
Include a valve at the start of your branched drain or laundry system that allows you to
water one section of your garden at a time. Water a new section each day.
Mulch Basin
Dig a 10-inch deep basin around the dripline
of a tree or shrub and fill it with mulch. The
mulch will soak up and hold the graywater.
giving roots more time to absorb it. The
upside down flower pot prevents mulch from
blocking the end of the tubing. Use old plastic
pots from the nursery, cut a hole in the side for
the tubing, and cut the bottom out so you can
see inside when it is in place.
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