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Gray Water For Irrigation A Coming Reality?01-30-13 | News

Gray Water For Irrigation A Coming Reality?

Arizona

Tucson City Council Reviewing Gray-Water Irrigation Requirement

The Tucson City Council voted unanimously recently to explore all options in regard to water conservation, including the use of gray water for irrigation in residential homes.

The staff recently recommended the council scrap the 2008 gray-water ordinance, which mandated that new construction within the city include plumbing so homeowners could connect a separate treatment, irrigation and storage system to water their lawns and gardens with used bath and washing machine water, if they desire.

Councilman Paul Cunningham said the ordinance was crafted with the future in mind. "CAP (water) isn't going to last forever. We're not going to have the Colorado River forever," Cunningham said. "We don't know what our water's going to be, and we need to have every tool in the shed to be able to conserve water long-term," he said. "By having homes built now fitted with pipes so they can easily transition into gray-water harvesting ... allows us another avenue ... for water sustainability into the next century."

Pre-fitted homes can also save homeowners money, since retrofitting a home can cost between $3,000 to $4,000, Cunningham noted.

He said the reason no one has taken out a permit yet is that backflow requirements and other issues have made installing a complete system cost-prohibitive. But he said those can be worked out with some "tweaking."

Proponents say gray water can save about 13,000 gallons of water per home annually. Critics point to a statistic from the National Association of Home Builders that shows for every $1,000 increase in the price of a home, more than 700 households are priced out of the home buying market.

Cunningham said he does not believe that a few pipes added to a new home can make a considerable impact on a potential sale. "You're going to have a tough time convincing me that a $500 pipe on a $150,000 project is going to affect the viability of the project," he said.

New Mexico Residents may see Water Bill increase, but not for Grey water users.

Alamogordo residents might see their base water rates increase in the coming year.

The Alamogordo City Commission passed an ordinance at its last meeting, that will should it be passed a second time provide for increases to city water bills.

Mayor Susie Galea said the increase in water rates will be used toward improvements of the city's waste water treatment plant. City records show the commission is also considering the rate increases to cover higher operating expenses.

She said the average homeowner will see an increase of about $1.40 per month, should the ordinance pass a second time, which is required in order for it to become law.

People who use gray water for irrigation purposes will not see an increase in their rates, she said. Galea said the commission decided to increase base water rates rather than water usage rates to avoid large bill increases on the city's top water users, places like Gerald Champion Regional Medical Center.

She said the city operates on a six-tiered water system, in which customers pay base rates based on their consumption.

Galea said the city implemented the system in 2003, the same year the city received recognition for its conservation efforts.

She said the ordinance should be on the agenda at the commission's next scheduled meeting. According to an agenda report, the commission adopted a separate ordinance in 2010 that implemented rate increases to cover increased operating expenses and costs of understructure of water and sewer lines associated with the "approved street capital program."

Texas

Texas A&M University is investigating the feasibility of gray water use for home landscape irrigation as a statewide initiative for conserving water resources. Gray water for irrigation is already allowed in some southwestern states, including parts of Texas.

"There has been interest in and discussion about the possible use of gray water for irrigating home landscapes, but so far little formal research has been done to validate its practicality," said Dr. Raul Cabrera, Texas A&M AgriLife Extension and Research Center in Uvalde. Cabrera said while it is difficult to precisely estimate the statewide potential for water savings through the use of gray water and application of the technology needed, it may reduce household landscape water use by up to 50 percent, depending on the size, type of landscape plants used and geographical location. "The average household uses as much as 50-60 percent of its water consumption for the landscape – grass, ornamental plants, trees, etc.," he said.

"Considering that the average family of four produces about 90 gallons of gray water per day, if this was used to irrigate a landscape, it could represent a significant water savings." Cabrera said this would be especially true for a large city such as nearby San Antonio, which has more than 1.3 million people in its metropolitan area. "Implementing the use of gray water for landscape irrigation across the state could mean a tremendous water savings in terms of acre-feet of water, contributing to the water use and conservation goals of the recently released 2012 Water Plan," Cabrera said. Using gray water is one of the easiest ways to reduce the need for potable water typically used in a home landscape, said Dr. Calvin Finch, director of the Water Conservation and Technology Center in San Antonio, which is administered by the Texas Water Resources Institute, part of the Texas A&M University System. "One of the low-hanging fruit projects that is often overlooked is use of gray water from households," he said. "Research results indicate that with minimum precautions water from our showers, bathroom sinks and clothes washers could be used to meet up to 10-15 percent of our overall landscape water needs."

San Francisco

Water recycling guidelines unveiled by San Francisco Department of Health

With the release of new rules for the use of nonpotable water in businesses and apartment buildings, San Francisco is riding a new water conservation wave.

The 23 pages of draft rules are part of San Francisco's effort to create a clear process for new commercial and residential developments to install nonpotable water systems for uses such as irrigation. The effort is part of a global construction trend to incorporate nonpotable water in development.

Within the last year, developers have expressed more interest in such systems, prompting the need for regulations, said June Weintraub, a senior health official with the Department of Public Health. Such systems conserve water, help building projects obtain LEED certification, and reduce a landlord's sewer and water costs.

The rules will govern collection and reuse of rainwater from rooftops, surface drainage and subsurface collection, as well as the two grades of building wastewater: graywater from showers and bathroom sinks, and blackwater from toilets and kitchen sinks. Depending on the source, such water can be used for irrigation.

In September, the Board of Supervisors unanimously approved legislation from board President David Chiu requiring city permits for such systems and the establishment of these rules.

The commission is now offering grants of up to $250,000 for large projects incorporating nonpotable water use. Projects would have to flush all toilets with nonpotable water or replace 40 percent of their total water use with nonpotable water to be eligible for a grant.

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