The practices of rainwater harvesting and conservation landscaping have been receiving an increasing amount of attention lately.  These practices are beneficial, and it is encouraging that they are receiving mainstream exposure.  But they are only part of the solution when it comes to dealing with our water challenges and conserving potable water.  The new reality for Central Texans is that water is becoming more scarce by the day, and we can only harvest rainfall if it rains.  Does that mean we should abandon water harvesting entirely? Of course not.  But water harvesting is only part of the solution.  There are other ways of reducing the use of potable water on ornamental landscapes that, when used in combination with water harvesting and conservation landscaping, have the potential to create a truly sustainable solution.


Change the Paradigm

In the last article on this topic, I alluded to the growth of conservation landscaping and xeric landscapes.  We are beginning to adjust to the idea that a lush, “country club” landscape is no longer practical everywhere in Central Texas.  Even if you “own” your own well, we are all drawing from the same dwindling water source.  As our water challenges increase, we must consider all of the tools we have available to keep Central Texas unique and beautiful.

With this said, let’s consider some of the other tools in our water resource toolbox.


1.  Rethink shower and wash: Greywater

Greywater is defined as wastewater generated from hand wash basins, showers and baths.  It is relatively clean and is safe for use on most plants.  More importantly, it is abundantly available.  How much water are we talking about?

The average shower = 25 gallons

The average bath = 35 gallons

The average bathroom sink = 3 gallons

The average load of laundry = 30 gallons

Consider a family of 4 that takes 2 showers and 2 baths, makes 4-6 trips to the sink, and does 1 load of laundry per day.

That equals approximately 300 – 400 gallons per day in greywater – enough to fully support a drip system for 750 – 1,000 s.f. of landscaping (about the size of an average front yard landscape bed).

There are downsides to using greywater, including the fact that it must be used quickly in order to prevent it from turning into blackwater, which is toxic to plants and humans.  Some filtration systems are capable of addressing this issue, but the more complex the system, the less practical it becomes in terms of maintenance and functionality.

Greywater has met some resistance in urban areas because of its perceived potential to contaminate ground water, and an arduous permitting process that mandates regular inspections.   Also, some plumbing systems require a certain amount of flow to function and those systems may depend on this water for proper functionality.

It may be more feasible in newer communities being built in rural areas because there are fewer regulations, and the systems can be designed to incorporate these functions.  As with any plumbing system, the most cost-efficient way to integrate the system is during new construction.  Unfortunately, it is not currently common practice to incorporate greywater systems into new buildings.  Therefore, if greywater use becomes common practice in 5, 10, or even 20 years – houses being built today will have a tremendous investment cost to overcome.


2.  Rethink flush: Effluent

As new communities develop outside of existing municipal sewer range, small treatment plants are being built to accommodate growth.  These smaller treatment plants can process wastewater and then pipe the treated effluent water back to customers for uses that do not require potable water, such as irrigation.  The important thing to know about effluent water is that it can be as clean, if not cleaner, than tap water.

You have probably seen signs in public areas that say something like, “This area watered by non-potable water.” These areas are typically being sprayed by treated effluent water.  In some places, treated effluent is even being introduced back into the drinking supply – including in China, Australia, and even California.  Read more about this practice here.


3.  Rethink reuse: Desalination

Once thought of as an impractical and costly alternative, the treatment of saltwater – also known as desalination – may be gaining more traction these days.  According to the Texas Desalination Association, the technique can be used not only on sea water, but also on brackish inland water as well.  There are currently more than 100 desalination plants in the state of Texas, and 40 of them are run by municipalities. Disposing of the waste created by desalination is a major financial challenge of the practice, however, improved technology and potential re-use of the byproducts might minimize this hurdle in the future.

Even if our lakes and reservoirs fill up again, the question is not if there will be another drought, but when it will occur.  The impact will be more immediate and more severe if the Central Texas population continues its current explosive growth.  Small investments in infrastructure now – such as potential pathways for future effluent service, or plumbing sleeves in new homes that might be converted to greywater later – are just some forward-thinking investments that might make the transition to sustainable water solutions quicker and easier. In the meantime, we must conserve, harvest, and reuse when possible to protect our water resources for future generations.

Photo credit: Bart Cayusa