Green Product Category: Plumbing

Access to fresh water is one of the world’s major geopolitical issues, yet in most of the U.S. we still use drinking-quality water as if it were free and unlimited. A substantial portion of this usage happens in buildings where leaky plumbing drips it away and fixtures designed decades ago use exorbitant quantities.

In some areas of North America, water is drawn from ground and surface sources at unsustainable rates—in other words, withdrawals from aquifers exceeding annual recharge rates. For much of the year, for example, the Colorado River no longer reaches the Gulf of California. In the U.S., we currently withdraw more than 300 billion gallons of fresh water per day from streams, reservoirs, and wells. Even in places where the water supply has traditionally not been a concern, problems are appearing as populations grow or precipitation patterns change (perhaps due to global climate change).

Water-saving designs

Toilet flushing uses over 4 billion gallons of water per day in the U.S. alone. While older toilets use about 4 gallons per flush, modern toilets conform to the requirements of the Energy Policy Act of 1992 and use no more than 1.6 gallons per flush (gpf). Simply replacing those older toilets with the new ones has been found to reduce a household’s overall water use between 10 percent and 30 percent. Some toilets use less water—or even none at all. The GreenSpec product list includes toilets that provide exceptional flush performance as determined by the Maximum Performance (MaP) testing protocol.

Other water-saving designs, devices, and systems are also included. The Energy Policy Act of 1992 also mandates that showerheads and faucets can use no more than 2.5 gallons per minute (gpm); some models use substantially less. Retrofitting these devices in older buildings is usually a very easy and extremely cost-effective investment.

Graywater recycling, wastewater treatment

Consumption of potable water can also be reduced by recycling graywater for nonpotable uses, such as irrigation and toilet flushing, although these systems may be prohibited by local health codes. In most of California it is legal to use graywater for landscape irrigation, provided the system is designed to meet certain conditions.

The drain on limited water supplies can also be reduced by harvesting rainwater. On some of the Virgin Islands, rainwater-storing cisterns provide the primary water supply to most homes. In parts of the U.S., it is not uncommon for collected rainwater to be used for landscape irrigation, toilet flushing, laundry and other nonpotable uses. For use as potable water, collected rainwater should be filtered and disinfected.

The other end of the plumbing system is wastewater disposal. Many conventional wastewater treatment systems, including both large municipal systems and private on-site septic systems, are inefficient and/or expensive. Alternative technologies—from composting toilets and recirculating sand filters to ecological wastewater treatment systems that rely on enhanced biological treatment processes—are available for systems of all sizes.