Earth Friendly Plumbing Services

Rainwater Harvesting and Greywater Systems

rainwater harvestingUsing alternate sources of water such as reclaimed greywater and harvested rainwater decreases the use of municipal or well water. Rainwater captured from roof surfaces and greywater captured from lavatories, laundry, tubs, and showers can be collected and used for landscape irrigation, saving water especially if you have a large yard or water intensive plantings.

Harvested rainwater and greywater, after being filtered and disinfected, can also be used for toilet flushing. Rainwater can be used for all water needs in the home if there is no other source of water available, but North Carolina plumbing codes currently limit indoor use to toilet flushing when other sources of water are available.

A rainwater collection and storage system on a home in North Carolina's Triangle Region with 1,000 sq ft of roof will collect about 34,000 gallons per year; enough for all toilet flushing and all of the outdoor needs for average family of four. Greywater is collected in a tank, filtered, and disinfected, and can be used for toilet flushing and subsurface irrigation. The table below shows the daily and annual use per person and for a family of four. The 15,000 gallons of greywater can be used to provide enough water to flush the toilets and meet about 50% of outdoor water needs.

  Daily per capita Annual per capita Family of 4
Indoor Use 70 gallons 25,500 gallons 102,200 gallons
Outdoor Use 30 gallons 11,000 gallons 44,000 gallons
Used for toilet flushing 27 gallons 9,900 gallons 39,600 gallons
Greywater generated 43 gallons 15,700 gallons 62,800 gallons


Contact us

NC Green Plumbing, Inc
PO Box 1385, Carrboro, NC 27510

Rainwater Harvesting Chapel Hill NC

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Fax Number

Fax: 919-338-8107

NC Green Plumbing