In dry regions of the United States, landscaping is a luxury. The lawns and gardens that one sees in wetter regions are not as common. Instead, dryscapes using rock and sand are often a better choice along with drought tolerant vegetation such as succulents and cacti.
But occasionally in dry places such as the southwestern United States, where water is scarce, you see a city that is more lush than you would have thought. That is more common in newer communities where housing developments have grown up in the last few years. In some such communities, you’ll notice that the parks, streets, and other common areas like community centers and schools look really green and well-watered, even while some of the private yards and not as well maintained.
What is going on here? It may have something to do with purple piping.
Source: Creative Commons via Wikimedia.com by Grendelkhan.
When most older cities were developed, they were done using the same water systems. But then came more population growth, droughts, and (in some areas) restrictions on water use. Every drop of water used on a park’s lawn is that much for people to drink or take showers in.
I have seen some where public fountains or ponds are normally a centerpiece of the community. Yet in drought years they may have to be drained and kept dry. Lawns at some parks and schools, also, have suffered cutbacks and often look more brown than green.
But as a backdrop, many cities and municipal areas have modern wastewater treatment facilities. That means that effluent (including sewage) can be treated to eliminate the sludge and impurities. Wastewater that is tertiary treated (that through three stages) is basically indistinguishable from any other drinking water. Let’s face it: every molecule of water in the world has been involved in some dirty activity sometime during its life on earth, even though it may have been cleaned up through being filtered naturally or evaporated in the millennia since.
Recycled water also is treated to a high level via filtration because most communities with this level of water treatment are reintroducing it back into the environment into a river, wetland, and aquifer, or other water source. A few areas even have permits to use it for agriculture, since the treated water is probably 99.9% the same as drinking water, and the .1% is only there because they are not able to warrant by law that it is completely pure.
Newer housing developments have the advantages of having newly-laid infrastructure, such as new pipes and electrical systems. In older areas, it costs a lot of money to tear up the streets and put in new pipes or cables. But these newer areas are able to incorporate more before they put in the new housing.
That’s where you often see purple piping.
In the world of pipes and conduit, there are different colors to make the function clear. As an article from Southern California Public Radio explained, cities in the U.S. generally use a common system for pipe coloring. Under that system, “blue is for potable water. Green is for sewers. Yellow signifies natural gas, oil, petroleum, or something else that’s potentially flammable. Orange is for telecommunications. Red is for power lines. And white is for marking where excavations and new pipe routes will go.” https://www.scpr.org/blogs/environment/2014/03/10/16035/purple-pipe-means-recycled-water-why-purple/
Purple was not being used, and so cities who incorporated recycled water into their projects began using it for that purpose. “Recycled water” a.k.a. (finely treated wastewater) can be used to irrigate many public areas. That’s why in some of these places, you will see really green spaces with lush lawns even during droughts and water restrictions. And if you look at little more closely, you also will notice that purple piping. In hot weather areas, the purple color tends to break down somewhat, often looking more pink than purple, or even a dull grey with just a hint of purple remaining.
So when you see pipes, sprinklers, drip systems, and plumbing boxes that are purple, that’s supposed to mean clean, recycled water used for irrigation. You’re not supposed to drink it. But dogs seem to think it’s pretty good for drinking also.
Source: Creative Commons via Flickr.com by Jay Galvin.
Images are public domain, by the author, or credited separately in the text.