Greywater: A Regenerative Solution

What is Greywater?

Greywater is gently used water from household activities such as showering, bathing, washing clothes, and using bathroom sinks. Instead of being discarded as wastewater, like the heavily contaminated water from toilets (blackwater), it can be redirected for other purposes, such as watering our gardens and fruit trees.

This distinguishes it from wastewater from toilets (blackwater), which contains fecal matter and dishwashers, which often contains harsh detergents that can kill plants and soil microorganisms.

🌱 Next Steps: Bring Greywater to Life

Now that you’ve estimated your greywater harvest, it’s time to explore the real-world systems that can make it happen. Below are three common types of greywater systems, each with a different level of complexity and impact.

🧺 Laundry-to-Landscape (L2L)

Ease of Use: ★★★★★ (Very Easy)
Estimated Cost: $150–$400 DIY in materials
Best For: Renters, DIYers, beginners, and homeowners as well.
What It Does: Redirects water from your washing machine directly to mulch basins in your landscape.
Why It’s Great:

• No plumbing changes required

• Legal in California without a permit

• Inexpensive and quick to install
  Perfect for: Fruit trees, ornamental plants, and shrubs

🚿 Shower-to-Flowers (Gravity Pipe or Branched Drain)

Ease of Use: ★★★☆☆ (Moderate)
Estimated Cost: $300-$700+ in materials
Best For: Homeowners, or renters with permission
What It Does: Channels water from your shower, tub, or sink to your yard using gravity thorough ABS or PVC pipe to mulched basins.

Why It’s Great:

• Works without power

• Can be customized to fit your yard’s layout and slope
  Perfect for: Established trees, perennials, hedgerows

⚠️ Challenges:

• Requires plumbing modification, which may need a permit

• Homes on slabs or with uphill gardens may not work

• Hard to spread the volume out over more than a few spaces

🛁 Whole-House Greywater System (Pumped)

Ease of Use: ★☆☆☆☆ (Advanced)
Estimated Cost: $700–$3,000+ in materials
Best For: Renovators, builders, long-term planners
What It Does: Collects greywater from multiple sources (sinks, tubs, laundry) and pumps it through irrigation zones in your landscape.

Why It’s Great:

• Maximizes reuse from nearly all greywater sources

• Can serve larger landscapes with automated irrigation

• Often integrated into custom home builds or major remodels
  Perfect for: Larger properties, regenerative homesteads, and those seeking long-term water resilience

⚠️ Challenges:

• Pump, filters, and controller system adds complexity

• Regular maintenance required (filter changes, pump checks)

• Permits and professional design are typically required

• High upfront cost and energy use (although minimal compared to total savings)

✅ Look for:

• Biodegradable and non-toxic ingredients

• Low or no sodium (avoid sodium lauryl sulfate or sodium chloride)

• No boron or borax (can build up and damage plants)

🚫 Avoid:

• “Antibacterial” soaps

• Products with bleach, boron, or optical brighteners

• Heavy-duty degreasers or fabric softeners

Soap Categories & Brands to Explore

Here are a few examples of greywater-friendly options (always double-check ingredients as formulas often change)  

🪴 Choose the Right Plants

Greywater is most suitable for non-root edible crops and ornamental species that exhibit tolerance to irregular moisture levels and water with low salinity.

Optimal plant selections include:

• Fruit trees (including citrus, fig, mulberry, guava, fig, and more): Fruit trees, once established, can thrive with greywater irrigation due to their deep root systems. The added nutrients in greywater can also enhance fruit production.

• Perennials (such as rosemary, lavender, and lemongrass): These Mediterranean herbs are well-adapted to drier conditions and can tolerate the occasional presence of soap and other substances in greywater. Their aromatic properties can also deter pests.

• Berries (including raspberries and blackberries): Berry bushes benefit from the consistent moisture provided by greywater, leading to increased fruit yield.

• Vines (for instance, passionfruit and grape): These vigorous vines can effectively utilize the nutrients in greywater, promoting healthy growth and abundant fruit production.

It is advisable to avoid the use of greywater for the irrigation of root vegetables (e.g., carrots and beets) and lawns. Root vegetables, due to their direct contact with the soil, may absorb harmful substances present in greywater. Lawns, on the other hand, typically require a more consistent and evenly distributed watering pattern, which can be challenging to achieve with a typical greywater system.

🧱 Shape the Land to Slow and Sink Water

The design of the greywater flow path should incorporate gentle slopes and mulch basins to facilitate the gradual dispersal and absorption of water into the soil as well as harvesting rainwater.

• Basins or swales should be employed to capture water at the root zone: These features help to contain the greywater and direct it towards the plant roots, where it can be most effectively absorbed. Swales, in particular, can also help to manage rainwater runoff, further enhancing the sustainability of the landscape.

• The pooling or runoff of greywater should be strictly avoided: Standing water can create breeding grounds for mosquitoes and other pests, and runoff can carry pollutants into waterways.

• Rainwater can help leach salts out of the soil: In areas with high salt content in the soil, rainwater harvesting can be integrated with the greywater system to help flush out these salts and improve soil health.

• Consider the topography of the landscape: The slope of the land will influence how greywater flows. Gentle slopes are ideal for distributing water evenly, while steeper slopes may require additional features, such as terraces or check dams, to prevent erosion and runoff.

⚖️ Is Greywater Legal? Understanding the Rules in California

Greywater systems are legal in California—and in many cases, you can install simple systems without a permit. However, there are important guidelines and distinctions you need to know to stay compliant and safe.

✅ No-Permit Greywater Systems

California allows “laundry-to-landscape” systems to be installed without a permit as long as:

• The system doesn’t alter plumbing inside the home

• Gravity is used (no pump added and the built in pump of the washing machine is allowed)

• Greywater is discharged below the soil surface, not sprayed

• No pooling or runoff leaves your property

• Water is used for ornamental or edible plants (except root crops)

• The system includes a way to easily switch back to the sewer/septic system

These guidelines are laid out in the California Plumbing Code, Chapter 15: Nonpotable Water Reuse Systems.

📄 Systems That Do Require a Permit

If your system:

• Collects greywater from showers or bathroom sinks

• Uses a pump (except from a washing machine)

• Stores greywater for more than 24 hours

• Modifies existing plumbing

• …you’ll likely need a permit from your local building department. However, do not be discouraged. There are also ways around these hurdles.

🏛 Local Variations Matter

While California allows greywater use, rules and enforcement vary by city and county. For example:

• Some cities require inspections, even for permit-exempt systems.

• Others may offer rebates or incentives to install water-saving systems.

We recommend checking with your local water agency or building department before installing anything beyond a basic laundry-to-landscape system.

Design a Regenerative Future, Rooted in Water Wisdom

Ready to take the next step in your journey? Our Permaculture Design Courses go beyond theory, equipping you with the hands-on skills to create resilient landscapes that reuse water, grow abundance, and regenerate the land.

💧 Learn from the Experts
Study with seasoned permaculture designers who specialize in water-harvesting landscapes, greywater systems, and perennial food forests.

🌱 Master Regenerative Tools
Get confident with greywater design, rainwater harvesting, earthworks, and integrated systems that support long-term soil health and food security.

🌎 Create Real Impact
Whether for your home, farm, or community, you’ll design systems that save water, grow food, and heal ecosystems—all while building your skills and confidence.

Take your passion for greywater and regenerative living further.