One of simplest answers to reducing water consumption is the use of greywater for landscape irrigation, flushing toilets and other non-potable needs. According to the National Resources Defense Council (NRDC), over half of our indoor water use can be considered greywater. It’s what households and commercial buildings generate from sinks, baths and showers, washing machines and dishwashers (toilet water is considered blackwater, not grey, and is not safe for reuse without heavy wastewater treatment facilities).
With 50% of the total water use in an average single family home in the U.S. going to landscaping, the redirection of greywater to outdoor irrigation alone could have a huge impact in water use overall. Yet the legality of greywater systems varies greatly not just in the United States, but around the world.
In Australia, a region that has grappled with its limited water resources for decades, over 50% of households use greywater systems for landscaping or flushing toilets. Mexico allows the use of greywater for outdoor irrigation. In New Zealand, some regions have embraced greywater systems as a necessary feature of new homes. But other countries have either been hesitant to develop greywater policies or have established such convoluted regulations that greywater systems are inaccessible for most households.
Legal greywater systems in the United States only date to 1989 when the first U.S. district, Santa Barbara, California, began allowing for its collection and distribution in its building codes. By 1992, 17 western U.S. states allowed for the legalization of greywater systems with the adoption of specific regulations (Appendix J to the Uniform Plumbing Code) but most states refused to play along. In the late 1990s and early 2000s, several states including California, Arizona, New Mexico and Texas, revised their codes to allow for the building of greywater systems but established such confusing legislation that only the most dedicated were willing to shell out the money and complete the paperwork necessary to pursue them.
Today around a third of U.S. states permit the use of greywater but each subjects residents to its own unique bureaucratic foibles. In Massachusetts, greywater systems are only permitted in homes with a composting toilet. In Florida, greywater is allowed for flushing toilets but not for watering outdoor plants. In Georgia you can collect greywater in buckets to water plants but the construction of any kind of simple irrigation system is prohibited.
So while we can all be glad Georgia isn’t regulating our buckets, it’s worth wondering why even those limited states that nominally allow greywater use make it so difficult for the average household to easily conserve water. It primarily comes down to questions of disease and environmental impact. So why don’t we study these potential impacts, you say? In fact, dozens of studies already exist providing no evidence that greywater is unsafe for non-potable uses.
An epidemiological investigation conducted in 2015 found that the use of greywater for irrigation in arid regions presents no additional risk of disease. Other studies have analyzed the safety of organic pollutants in greywater and found that their presence is typically in such low concentrations that they do not present a significant risk to the environment or the people or animals in it. And while some household products have greater potential for leaching higher chemical concentrations into lawns, flowerbeds and toilet tanks, a bevy of non-caustic, biodegradable alternatives are already on the market and ready for use.
Heeding the scientific evidence, Arizona has already taken a cue from Australia, developing a simple, safe and affordable policy for greywater irrigation. In Tucson, policy has gone so far as to mandate that new single-family home construction must include dual plumbing to capture greywater. Rather than place the burden of system construction on homeowners, the city even offers them a fat rebate for their trouble.
Elsewhere, the slow pace of greywater regulation and its uneven and confusing legislative code has led to an underground movement of rogue water conservationists willing to flout the law to decrease their consumption. Since the late 1990s, the Greywater Guerillas (now Greywater Action) have rigged thousands of unpermitted greywater systems around the East Bay outside of San Francisco, California. With a simple unpermitted system running around $100, this option is not only far cheaper than a permitted system (which runs between $2000 and $10,000 per household) but can be constructed far more quickly than navigating the nonsensical California greywater permitting system. There are currently an estimated 8,000 unpermitted greywater systems in the state for every one built under permit.
With continuing drought in the west, diminishing lakes and reservoirs in the north and south, and a dropping water table around the country, we can expect that eventually state legislation will catch up with the need to consume less water as a nation. But, if the history of the greywater movement in the U.S. teaches us anything, we can expect a whole lot more homeowners to go rogue before it does.