Why you should care
Because bathwater is good for more than just bathing.
“CRITICAL WATER SHORTAGE! DAMS AT 11.2%,” reads a roadside sign that usually notifies drivers of accidents. In the once-leafy suburbs of Cape Town, South Africa — where I live — it’s now considered a sin to have a green lawn or take a luxurious soak in the tub. These days I shower (two minutes, no more) with buckets at my feet, which, once full, are used to flush the loo. And my kids bathe in 2 inches of water, which is then diverted onto a flower bed. Cape Town has a Mediterranean climate, but the combination of an expanding population (3.7 million in the metro area, growing at 2.6 percent per year), an extended dry cycle and a lack of municipal foresight has brought the situation to a dramatic and desiccated head.
Against this backdrop, graywater recycling companies have sprung up in Cape Town and other parched areas of South Africa like daisies after a desert cloudburst (if only). One expert estimates that home recycling installations in the city have jumped from around 300 per year in 2005 to 6,000 in 2017. Gray water is the water that comes out of baths, showers, hand basins and washing machines — about 33 percent of the water used in an average house with a yard and more than 50 percent in an apartment without a garden. Instead of ending up in sewers, it’s repurposed for garden irrigation (cheap and easy), flushing toilets (slightly more complicated and expensive) and taking showers and doing laundry (pricey and complex). According to local installers, a basic garden irrigation system for an average family home in Cape Town costs about $1,000 and cuts consumption by around 30 percent, for annual savings of $150.
It is absolutely preposterous that any drinking water should ever be used for irrigation purposes.
Jeremy Taylor, founder, Water Rhapsody
On its own, reusing gray water will not solve the world’s water problems, but coupled with improved consumption habits and rainwater harvesting it could go a long way toward reducing our reliance on municipal water. Intewa, a German water-solutions company, reports a 400 percent increase in sales on domestic units in the past three years — albeit from a very low baseline. What’s more, this growth has been steady in all 20 countries where Intewa operates.
Jeremy Taylor of Water Rhapsody is the graying grandfather of gray water in South Africa. In the 1980s, it dawned on this former city councilor that Cape Town would probably run out of water by 2005 (it ended up taking 10 years longer), and so he started looking for solutions. After a few years of tinkering, Taylor founded Water Rhapsody in 1994. His breakthrough product was a simple “sump and pump” irrigation system that diverts water directly to a sprinkler when a shower or washing machine is turned on. He has since added the aptly named Second Movement system that uses gray water to flush toilets. “It is absolutely preposterous,” says Taylor, “that any drinking water should ever be used for irrigation purposes. The current water restrictions are how it should be all the time.” (In the past two years, restrictions and public appeals have enabled Cape Town to reduce its daily water consumption by 40 percent.)
Oliver Ringelstein, owner and head engineer of Intewa, markets the Aqualoop system, which uses biological agents and ultrafine filters to restore water quality to the point where it’s not quite potable but plenty clean enough for everything else. Although the Aqualoop is the first graywater system to receive certification in the U.S. from the nonprofit National Sanitation Foundation, it’s beyond the budget of most consumers — a standard domestic installation costs approximately $5,000. “Weirdly, graywater systems are quite popular in watery Germany because our water and sewerage prices are so high,” says Ringelstein. “But prices in many water-scarce countries are ridiculously low.” In Germany, the systems pay for themselves in about 10 years, according to Ringelstein.
So, who could possibly oppose water conservation that relies on systems installed and maintained by private users? Municipalities, that’s who. It doesn’t make economic sense for them to advocate water recycling when they rely on water and sewerage tariffs to balance budgets. Nevertheless, the South African Department of Water and Sanitation does acknowledge that the country is going to have to “rethink our conventional sanitation solutions and invest in more sustainable alternatives.”
South Africa is quite lucky with legislation, Taylor notes. Some countries have implemented much stricter controls on gray water. Laura Allen from Greywater Action, a California nongovernmental organization, confirms that, by default, graywater reuse in the U.S. is prohibited, but she also notes that public demand during long droughts can force changes in state regulations. “California has a lot more support for gray water since simple systems — i.e., garden irrigation systems — were legalized there,” she explains. “Dozens of water districts and cities, including Santa Clara and San Diego, have incentivized their installation.”
Kevin Winter, lead researcher at the University of Cape Town’s Future Water Research Institute, raises another concern: Puddles of gray water on paved areas could, in extreme circumstances, become breeding grounds for mosquitoes and other transmitters of infectious diseases such as cholera. For health reasons, Winter says, legislation needs to ensure that graywater installations are equipped with valves to divert excess gray water to sewer systems (both Taylor’s and Ringelstein’s systems do this).
I ask Ringelstein what the water system in the house of the future will look like. “A lot like mine,” he says, laughing. Through a combination of graywater recycling and rainwater harvesting his family has manged to reduce their water consumption by 90 percent. All that stands between them and complete independence of the water grid is a sewage treatment system. And here I sit, flushing toilets with buckets and fretting about my dahlias.