Rainwater Harvesting An Easy Way To Practice Water Conservation
By Scott Kriner, Green Metal Consulting
Today while looking out my kitchen window and watching a brilliant red cardinal dance in the snow-covered bushes, I actually had thoughts of rainwater harvesting. At this time of the year we don’t see much in the way of rainwater in the weather forecasts of the Northeast. More the norm is snow, sleet, snow, ice, cold, and more snow.
The thought of rainwater harvesting was sparked by an article that had appeared in our local newspaper last autumn. It described a local homeowner who had installed a simple rain barrel and used his existing gutters and downspouts to capture the rainwater for other uses. One of those uses, which is applicable to this time of year, was to fill empty milk jugs with water and allow them to freeze in the winter. The homeowner then brings in one jug at a time to place in his refrigerator. He claims that while doing this, his refrigerator rarely runs during the winter months. The other uses of his captured rainwater were for irrigation and for toilet flushing. But there was no special plumbing involved. The irrigation was basically a sprinkling can to use for flowers, his garden and small plants around the house. And he uses the captured rainwater in his toilets by bringing the water in milk jugs and filling the toilet tanks to displace the need for potable water. Yes, it sounds like a high-maintenance practice, but it saves water in the long run.
Water efficiency in homes and buildings continues to be an important aspect of green building strategies. Not only is conserving and restricting the use of potable water or managing stormwater runoff examples of water efficiency, but they are also cost saving measures. In many parts of the country, including my hometown, we don’t think too much of the cost of water. It’s not on our radar screens like the cost of gasoline, electricity or natural gas. In fact, the cost of water around the country varies depending where you are. In water-poor locations like Georgia or the Southwest, water is expensive and therefore water efficiency is a priority. On the other hand, where water is abundant and considered cheap, like in the Midwest and some parts of the East Coast, water efficiency is rarely considered to be important. However, some consider water to be part of any building’s utility portfolio.
The US Government recently projected that at least 36 states will face water shortages within five years. Key water supplies at high risk include the Chattahoochee River and the Colorado River systems. Water scarcity can be driven by population growth, inappropriate land use, poor water-resource management and decaying infrastructure. According to a 2003 report by the American Water Works Association, the US is losing about 15% of its drinkable water each year (2.2 trillion gallons of treated water) because of leaks from deteriorating metal pipes.
The USGBC’s LEED program is doing its part to keep water efficiency prominent in the sustainability of a building project. In the Existing Building – Operations and Maintenance LEED program, a prerequisite is in place to mandate a 20% reduction in building water use, using a baseline calculation set by the 2006 edition of the Uniform Plumbing Code. In addition to the prerequisite, water efficiency strategies are covered in credits that provide up to 12 total points.
The first step toward conserving water is to know how much you are using. The easiest way to do that is to look at the water bill. It’s important to remember that water may be flowing in places that no one is observing. Facility managers are beginning to meter water usage. In some buildings metering of water is essential to look for ways to reduce usage in irrigation, indoor plumbing fixtures and fittings, cooling towers, domestic hot water or other process water.
There are many novel technologies being introduced in the area of water efficiency improvements. Some examples include double-flush toilets, waterless urinals, re-use of graywater for bathroom fixtures, irrigation systems based on captured rainwater, and even potable water from rainwater harvesting in some places.
More local jurisdictions are beginning to permit graywater recycling as long as no one comes into contact with the water. It will likely become more common practice in new construction. Some cities are contemplating “blue lines” that will provide graywater from the public water works to buildings/homes and plumbed directly into toilets, washing machines and irrigation systems.
Many ignore the fact that there is embodied energy in water. Energy is used in the pumping of water from its source to a treatment plant, the treatment process itself, pumping water from the treatment plant to the home or building and heating the water for bath and washing purposes. This underscores the importance of using potable water only when absolutely necessary. Washing cars, flushing toilets and watering the lawn with potable water is unnecessary and costly. And let’s not forget about the flipside of the water/energy relationship. The production of electricity uses significant amounts of water, primarily for cooling the generating equipment. So any efforts to reduce energy consumption can have an indirect beneficial effect on conserving water as well.
According to Environmental Design and Construction magazine, American public water supply and treatment facilities consume about 56 billion kilowatt hours annually – enough electricity to power more than 5 million homes for an entire year. As local communities face water shortages and demand for water grows, we are pumping water from greater distances and from deeper in the ground – all increasing the amount of energy used. Nationwide, drinking water systems and wastewater systems use as much energy as the pulp and paper and petroleum industries combined in order to treat our water supply.
With all of this said, the simplest method of reducing the use of potable water is often integrating a rainwater harvesting system with the roof. A metal roof can be an ideal platform for that type of integrated system. The surface of a metal roof is smooth, inert, resists biomass growth, contains no particulate matter, corrosion resistant and easily adaptable to small or large water catchment systems. In some cases, with proper NSF certification, the rainwater collected from a metal roof surface can be drinkable, with proper filtration, sterilization and treatment. It certainly is the case in Australia and in other countries in the world.
After the snow, ice and slush has melted away, and the cardinals are joined by robins, crows, starlings and budding trees, our minds will turn to springtime. As the grass turns from a dull brown to green, color and flowers and plants break through the ground, we can all think about using our potable water more efficiently to lower the environmental impact of our buildings and homes.
Scott Kriner is the president and founder of Green Metal Consulting Inc. He is a LEED Accredited Professional who began his career in the metal construction industry in 1981. His company is a member of the U.S. Green Building Council, the California Association of Building Energy Consultants and the Residential Energy Services Network (RESNET). Scott can be reached by email at skriner1@verizon.net or by phone at (610) 966-2430. You can also visit him on the web at www.greenmetalconsulting.com.
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