Self-Sufficiency
Make an Off-Grid DIY Greywater System for Your Garden
From our morning showers to our evening dishes, water is often a resource we take for granted. Yet, the reality is that the world’s demand for water has long surpassed its supply, and with the looming specter of climate change, droughts and water shortages are becoming increasingly common.
Reusing wastewater may not seem worthwhile for those with access to municipal water systems. However, for those who rely on well water for both personal and agricultural uses, particularly in arid regions where every drop is precious, the value of water cannot be taken for granted.
An off-grid DIY greywater system is a sustainable solution that conserves water and reduces strain on septic systems. By diverting greywater from sinks, showers, and washing machines, homesteaders can efficiently irrigate crops and landscaping while minimizing their reliance on potable water. In this article, we’ll look at the ins and outs of creating your own greywater system to embrace water conservation and self-sufficiency in your home.
Greywater vs. Blackwater
It’s essential to understand the dos and don’ts of managing household wastewater. Greywater is not pristine, but it’s far from being too contaminated for reuse, provided certain precautions are observed. Greywater is generated from daily activities like bathing, laundry, and dishwashing. Blackwater comes from toilets and includes human waste and other pollutants. It must be directed to sewage or a septic system.
While greywater isn’t typically suitable for drinking due to the challenges of purification, it’s still an invaluable resource for household use. The average daily greywater production per person in developed countries is around 25 gallons or approximately two-thirds of total household wastewater. It’s an opportunity for thoughtful homeowners to harness and lessen their environmental footprint.
In the following sections, we’ll delve deeper into greywater management and how you can repurpose this resource for a more sustainable home.
The Benefits of Greywater Recycling
Greywater can be safely used for various household applications. Collecting bathwater with a bucket for toilet flushing is the simplest and most obvious, but irrigation is a less labor-intensive and practical option (and won’t leave a ring in your bathtub). Directing greywater to your garden can nurture a lush landscape with less reliance on potable water.
Certain plants thrive when irrigated with greywater with little or no issues. Wetland plants, decorative foliage, tomato plants, grape vines, berry bushes, and fruit trees are all excellent candidates. However, it’s essential to avoid using greywater on root vegetables or plants with edible parts that come into direct contact with the soil, as this could lead to contamination. Unpurified greywater should also not be used for lawns since contaminants may come into contact with people and pets.
While greywater reuse is generally permitted across the USA, it’s important to familiarize yourself with local regulations. Some areas may require permits or have specific guidelines in place. There’s nothing worse than putting in hours of work and then getting a thumbs down from the health department!
There are may options to choose from when diverting greywater.
How to Make a DIY Greywater System
Before installing a greywater system in your home, consider the different types of systems available, your landscape and garden soil needs, and compatibility with your home’s plumbing.
Decide which greywater sources you’ll utilize, such as washing machines, bathroom sinks, and showers. Determine the volume of water your plants can absorb and consider the elevation of your home relative to the surrounding land.
The primary components of a greywater system include:
- Mulch for absorbing water and promoting soil filtration;
- Drip lines for underground irrigation;
- Three-way diverter valve, which enables switching between sewer/septic and irrigation;
- Surge tank, which regulates the distribution of greywater;
- Optional filter system to remove hair and lint;
- Plumbing pipes for directing water flow;
- Pump, if gravity distribution is not feasible;
- Landscaping materials such as filter fabric, mulch, and gravel.
While the cost of materials is modest and should only be a few hundred dollars, it could cost thousands if it’s necessary to hire a plumber.
There are two main methods of greywater harvesting:
- Washing Machine: Greywater can be pumped outside directly from the washing machine. Ideally, the washer should be above ground level and preferably next to an exterior wall. A diverter valve is used to switch between the outdoor pipe and the drain
- Bathroom Sinks and Showers: More extensive systems connect drains from bathroom sinks and showers to a diverter valve, directing water outdoors. This system is easier to install during home construction than as a retrofit since it requires altering the plumbing. It’s advisable to consult a professional, as some jurisdictions require licensed plumbers for alterations to drainage systems.
Reusing dishwater is more complicated, and some jurisdictions don’t allow it because it contains grease and food particles. Some DIY setups run dishwater through a grease trap, which is basically a pail that allows grease to separate, and use a natural filter like mulch to remove food particles.
Greywater can be channeled directly into the garden or stored temporarily in a surge tank. Typically buried outdoors, the tank should include an overflow outlet directed to waste and must not retain water for more than a day to prevent pathogens. Distribution can occur via gravity or with the assistance of an electric pump.
A DIY surge tank with filter and electric pump. YouTube/TechnowledgeVlog
A system of branched pipes directs greywater to designated areas of the garden. Proper slope and drainage are crucial to ensure even water distribution. Consider testing the water flow with a garden hose before connecting to the greywater outlet. Rather than draining directly into the soil, the pipes usually drain into buried pots or similar containers inside a mulch or gravel-filled trench. The trench surrounds the area to be irrigated in a circle or semicircle to absorb the water quickly and capture impurities. When complete, the system is invisible and automatic but can be easily accessed for inspection and maintenance by pulling back the covering.
Alternatively, the water can be pre-filtered and passed through perforated pipes buried under gravel or mulch. You can make a simple and affordable DIY greywater filter by combining a layer of sand between two thinner layers of gravel. Wetland plants can help aerate the filter and create a welcoming habitat for wildlife. For more information, see this pdf guide.
If you have an attached greenhouse, you can use greywater as an additional source of warmth for your plants and reduce the risk of frozen pipes during winter months.
For more help with greywater system installation, the San Francisco Public Utility has a downloadable guide covering various greywater system types and installation procedures.
Issues with Greywater Recycling Systems
While greywater recycling systems offer numerous benefits, they also present challenges that must be addressed to maintain the integrity of your system and protect the environment.
Care must be taken to prevent greywater from pooling on the surface, as stagnant water can harbor pathogens and emit unpleasant odors. Proper drainage and slope design are essential to ensure the soil efficiently absorbs greywater without causing surface runoff. A diverter valve is necessary for managing greywater flow, especially during periods of heavy rainfall when the soil may become saturated. It allows you to switch between the greywater system and sewer/septic to prevent excessive watering and stop water contaminated by chemicals or human waste from reaching your plants.
When diverting water to a greywater system, it’s crucial to be mindful of what goes down the drain. Chemicals such as bleach, salt, and boron can harm plants and disrupt soil ecosystems. Opt for biodegradable, unscented soaps, detergents, and shampoos to minimize the impact on your garden (and yourself). Since greywater is not pH neutral, it may affect the soil’s acidity, potentially impacting acid-loving plants. Monitor soil pH levels regularly and use organic remedies like compost to maintain optimal plant health.
Microplastics shed from synthetic fabrics during laundry cycles can also contaminate soil and food plants over time. One option is to install a microplastic filter on your washing machine to trap these particles and prevent their introduction into your greywater system.
Greywater should not be stored for extended periods, as it contains organic matter that can decompose and promote bacterial growth. It should never be discharged in a manner that could lead to runoff into storm drains, waterways, or neighboring properties. Ensure that your system is designed to contain and distribute water responsibly, minimizing the risk of environmental contamination.
Finally, verifying that your system complies with state and municipal regulations is important before installing a greywater recycling system. While it’s tempting to skirt the system, consulting local authorities and obtaining necessary permits will offer peace of mind in the long run.
Conclusion
When properly installed and maintained, a DIY greywater system can reap significant benefits, from saving water to helping the environment. The key to success with greywater lies in careful planning and attention to detail.
Be sure to consider both the costs of installation and how much time you want to spend on upkeep. Complex systems require more maintenance and are more prone to problems. Start small and decide whether to expand your system after at least a year of testing.
An ideal setup should seamlessly integrate into your daily life, letting your garden utilize all the greywater you produce and minimizing the need for watering. Don’t forget that greywater recycling is just one piece of the puzzle in reducing water consumption. Prioritizing water-efficient appliances and shower heads, drought-resistant landscaping, rain barrels, composting toilets, and other conservation measures are the foundation of any sustainable water management strategy.
Ultimately, off-grid strategies like greywater recycling encourage us to think consciously about our resource consumption, fostering self-reliance and reducing our environmental impact for future generations.
Featured image: Pixabay/Hans Hansen