Most people aren’t familiar with the term “grey water” and are not even sure what it is. In the world of self-sufficiency, interest in the use of grey water has seen a steady rise over the years and more people are coming around to the idea of processing their grey water into something useful. But what exactly is this “grey water” and how can you use it to benefit your household?
What is Grey Water?
Grey water (or gray water) refers to the relatively clean wastewater that flows from household sources, such as showers, bathtubs, sinks, washing machines, and kitchen appliances. Unlike “black water” (water from toilets), grey water does not contain high levels of contaminants or pathogens, making it suitable for reuse under specific conditions. However, grey water can contain traces of dirt, food, grease, hair, and cleaning products, which, if treated and managed correctly, can be recycled for non-potable uses.
Typically, grey water accounts for 50-80% of household wastewater. By diverting this water for purposes other than drinking or cooking, households can create an additional source of water for their garden, while lessening the burden on wastewater treatment facilities.
Benefits of Grey Water Recycling
Grey water recycling offers numerous environmental, economic, and social benefits. Here are some of the main advantages:
Water Conservation:
Reusing grey water reduces the demand for fresh water, helping to conserve local water resources. In regions facing water scarcity, grey water systems can play a vital role in maintaining a stable water supply.
Reduced Water Bills:
By reusing grey water, households can cut down on their utility bills, saving money on both water and sewage costs. This can be especially beneficial in areas where water is expensive or where there are strict water usage regulations.
Environmental Impact:
Grey water systems reduce the amount of water entering sewage systems, lowering the energy and resources required to treat wastewater. Additionally, grey water recycling helps recharge groundwater and maintain a healthy balance in the local ecosystem.
Improved Soil Fertility:
When used for irrigation, grey water can add nutrients like nitrogen and phosphorus to the soil, promoting plant growth without additional fertilizers. However, not all grey water is suitable for every type of plant, so careful planning is necessary.
Is Grey Water Safe to Use?
Grey water can be safely reused for several purposes, but it does require careful handling to avoid potential health risks. Grey water may contain bacteria, chemicals, and other contaminants from cleaning products, which, if not managed correctly, could lead to soil and plant damage or pose health risks.
The key to using grey water safely is to avoid contact with humans and animals, limit its use to non-edible plants, and use biodegradable cleaning products to reduce the amount of chemicals in the water. With appropriate precautions, grey water can be an effective and safe resource for numerous non-potable uses.
Grey Water Systems
To use grey water effectively, various systems are available, ranging from simple DIY setups to advanced filtration systems. These systems are generally classified into two main types:
Simple Direct Systems:
These systems divert grey water directly from the source (such as a washing machine) to an outdoor irrigation area. They are affordable and easy to install but require careful planning to avoid water pooling and ensure proper drainage.
Treatment Systems:
Advanced grey water treatment systems filter and disinfect grey water, allowing it to be stored safely for longer periods or used in more applications. These systems may involve settling tanks, sand filters, and biological treatment processes to remove contaminants.
The type of system best suited for a household depends on factors like water quality requirements, budget, and local regulations.
How to Use Grey Water in Everyday Life
There are numerous ways to incorporate grey water into your daily routine. Here are some practical methods for reusing grey water in your home and garden:
1. Irrigating Non-Edible Plants and Lawns
One of the most popular uses of grey water is irrigating gardens, specifically non-edible plants, trees, and lawns. Grey water from showers, bathroom sinks, and laundry can contain beneficial nutrients that help plants thrive. However, it’s important to follow these guidelines:
Use biodegradable, plant-friendly soaps and detergents to avoid harmful chemicals that can damage plants or soil.
Direct grey water below the soil surface using a drip irrigation system or subsurface emitters. This prevents human contact with the water and reduces the risk of contamination.
Rotate irrigation areas to prevent the accumulation of salts or other residues in the soil.
Avoid using grey water on edible plants, as the contaminants in the water could pose health risks.
2. Flushing Toilets
Reusing grey water for toilet flushing is another effective way to save water. While this requires a bit of modification to the plumbing system, many homes install a grey water system that diverts water from bathroom sinks or showers to toilets. This is particularly effective in households with high water usage, as flushing toilets can account for up to 30% of a household’s water consumption.
3. Washing Outdoor Areas and Vehicles
Grey water is suitable for tasks that don’t require clean water, such as washing outdoor patios, sidewalks, and vehicles. Grey water from bathtubs and showers works well for these purposes and can be collected in buckets or stored in tanks. However, avoid using grey water with excessive soap or chemicals, as these can pollute the surrounding environment or damage plants.
4. Creating a Constructed Wetland for Grey Water Filtration
Constructed wetlands are a natural filtration system for grey water. These systems mimic natural wetland environments, using plants, soil, and gravel to filter out contaminants. Once the grey water passes through the wetland, it’s cleaner and can be used for irrigation or other non-potable uses.
A constructed wetland is relatively easy to set up and is ideal for homeowners who want to reuse grey water sustainably. It can also become an attractive feature in the garden, providing habitat for wildlife and enhancing the garden’s biodiversity.
5. Laundry-to-Landscape Systems
Laundry-to-landscape systems are designed to capture grey water from washing machines and divert it directly to outdoor irrigation areas. These systems typically don’t require treatment, as washing machine water can be directed straight to the soil. Laundry-to-landscape systems are cost-effective and simple to install but require the use of phosphate-free and low-sodium detergents to protect plants and soil.
Important Considerations and Limitations
While grey water recycling is beneficial, it’s essential to be aware of certain limitations and considerations:
Follow Local Regulations:
Regulations regarding grey water use vary widely, and some regions have strict guidelines or permit requirements. Make sure to consult local authorities and follow any laws regarding grey water recycling.
Avoid Storing Grey Water:
Stored grey water can quickly become a breeding ground for bacteria, leading to foul odors and health risks. Most grey water systems are designed for immediate use, so it’s best to apply grey water to plants or flush toilets soon after collection.
Monitor Water Quality:
Pay attention to the chemicals and cleaning products used in the household, as they directly impact grey water quality. Opt for eco-friendly, biodegradable products to ensure grey water remains safe for the environment.
Seasonal Use:
In areas where rainfall is seasonal, the need for irrigation may fluctuate. During rainy months, grey water may not be necessary for irrigation and can be redirected or used in other areas.
Setting up a system to collect and filter grey water may not be for everyone, and also might not be necessary. The higher the cost of water and the remoteness of where you live will be the biggest factors in whether it’s worth using grey water, but unless you have problems in these areas that rain collectors can’t solve, it may be an unnecessary expense.
