One of the most effective ways to reduce water consumption in a tiny house is by implementing a greywater system.
These systems capture and recycle water from sinks, showers, and washing machines, giving it a second life for tasks like irrigation or toilet flushing.
By reusing greywater, tiny house owners can minimize waste, conserve resources, and create a more sustainable living environment.
In this article, we’ll dive into everything you need to know about the greywater system for a tiny house or ADU.
- Greywater comes from sinks, showers, and washing machines.
- Greywater can be used for toilet flushing or irrigation.
- Greywater systems help conserve water and promote sustainability, a core value in the tiny house movement.
- Using the right products is essential for safe greywater reuse.
Words to Know
Potable Water – Safe for Drinking or Consumption
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3 Water Systems in a Tiny House or ADU
There are three types of water systems in a tiny house:
- Fresh or clean water (potable)
- greywater (non-potable)
- blackwater (non-potable)
Freshwater is where it all starts.
This is the water you use for drinking and consumption.
Greywater vs Blackwater
There are two types of wastewater: blackwater and greywater.
Black water is the sewage waste from toilets (including bidets), typically stored in holding tanks and later disposed of at dump stations.
Greywater is the wastewater from:
- kitchen sink
- bathroom sink
- shower
- washing machine
It may contain soap, food particles, grease, and dirt, but it is generally safe to reuse for non-potable purposes.
What is a Greywater System for a Tiny House?
A greywater system typically consists of a few components that work together to filter and recycle the water.
These systems require a collection tank to gather the greywater and filter it to remove any solids and contaminants.
Some systems use simple filters, while others might employ more advanced treatment processes for future water use.
Once filtered, the treated greywater can be diverted to an irrigation system for watering plants or even reused for flushing toilets, depending on the setup.
The components of these systems are designed to ensure that water is reused efficiently for significant water conservation.
Managing Wastewater in a Tiny House
In traditional homes, water disposal is handled by municipal sewage systems. It all just goes down the drain and is forgotten about. At least until you get the bill for it.
For tiny house owners, there is much more intention in the handling of the wastewater, especially if you are living off-grid or are mobile.
Even if all you do is reuse the greywater to flush the toilet, you could save thousands of gallons per year.
If you invest in a more advanced greywater system so you can use the water for laundry, you can almost double your water savings.
| Usage (per year) | Gallons |
|---|---|
| Toilet Usage (per person) | 3,650 |
| Laundry Usage (4 loads a week / 15 gallons of water per load) | 3,120 |
| Total water | 6,770 |
Managing Wastewater in an ADU
Some ADUs are not connected to the main sewer system of the property, requiring alternative solutions for wastewater management.
This means owners could consider a composting toilet to eliminate the blackwater and use greywater systems to handle water from sinks, showers, and appliances.
Find Greywater Codes and and Policy in Your State
Do you know if you can use greywater in your area? If not, find the greywater code for your state by visiting this article.
Cost of Greywater Systems
Installing a greywater system in a tiny house or ADU can be a cost-effective investment in the long run.
The initial setup costs vary depending on the complexity of the system. You can go simple or you can go fancy.
Simple bucket collection methods can be implemented for free or under $50, while more advanced systems like branched drain systems or surge tanks can range from $200 to $1,000.
Commercial greywater filtration systems can cost upwards of $2,000 but offer greater efficiency and ease of use.
Long-term savings from a greywater system come primarily from reduced water bills, especially in areas with high water costs.
Some local governments offer incentives or rebates for installing sustainable water management systems, further offsetting initial costs.
Benefits of Using a Greywater System in a Tiny House or ADU
There are plenty of great reasons!
✅ Save Money on Water Bills – A greywater system reduces overall water use, helping you conserve drinking water and save thousands of gallons each year.
✅ Less Hassle for Tiny Homes on Wheels – You’ll need fewer stops to refill fresh water and can carry less, which reduces your home’s overall weight.
✅ Help Conserve Precious Water Sources – Recycling water protects valuable resources, which is especially important as the world faces potential shortages.
✅ Support a Thriving Garden – Greywater irrigation helps plants grow, making it a great option for dry climates where water conservation is critical.
By installing a greywater system, you’ll save money, reduce your impact, and create a more sustainable tiny home. 🌱💧
Environmental Benefits of Greywater Recycling
Beyond saving money, a greywater system helps reduce the strain on municipal water supplies.
🚰 Ease Water Shortages – Many cities face water shortages. Reusing water at home reduces the demand for freshwater resources.
🏭 Reduce Wastewater & Energy Use – Properly managed greywater lowers the amount of wastewater sent to treatment plants, cutting down on energy use and chemical treatments.
🌱 Improve Soil Health – Greywater from sinks and showers contains organic nutrients that nourish plants, reducing the need for synthetic fertilizers.
🌿 Support a Sustainable Garden – Greywater irrigation keeps plants thriving, especially in dry climates where water conservation is crucial.
Installing a greywater system not only benefits your home but also supports a healthier planet. 💚♻️💧
Innovative Uses for Greywater Beyond Irrigation
While irrigation is the most common use of greywater, tiny homeowners can explore other applications.
For instance, greywater can be used for:
- exterior house washing
- driveway cleaning
- cooling systems in warmer climates
- laundry reuse (with advanced filtration)
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Types of Greywater Systems
There are various ways to manage greywater in a tiny house or ADU, depending on your setup, location, and budget.
| Type | Description |
|---|---|
| Bucket Collection | The simplest way to repurpose greywater is by placing a bucket under your sink or in your shower to collect wastewater. You can then manually use this water for flushing toilets or watering plants. |
| Sewer or Septic Connection | If your tiny home or ADU is connected to a sewer or septic system, you can direct greywater there. While this doesn’t recycle water, it is the most straightforward disposal method. |
| Wetland Filtration | Creating a small wetland or pond allows excess greywater to be naturally filtered through vegetation and soil. This method works best for those with permanent setups and access to sufficient outdoor space. |
| Gravity-Fed Filtration | If your tiny house is positioned on a slope, you can create a simple gravity-fed filtration system using a series of buckets or barrels to remove impurities before directing the water to a garden or irrigation system. |
| Surge Tank System | A surge tank is a large barrel or drum that slowly releases greywater through a connected hose. This allows for controlled drainage, preventing flooding or over-saturation of your soil. |
| Branched Drain System | Ideal for permanent tiny homes, this system distributes greywater through a network of branching pipes to mulch basins, allowing water to be gradually absorbed by plants. This system is low-maintenance but requires initial installation effort. |
DIY Greywater Systems
If you are handy and want to save a ton of money consider a DIY greywater system. Here is more information to get started.
Best Practices for Recycling Greywater from Showers and Sinks
To get the most out of your greywater recycling efforts, it’s important to follow some best practices.
| Best Practice | Description |
|---|---|
| Use Biodegradable Soaps and Cleaners | Always use biodegradable soaps and cleaners to minimize the impact of chemicals on your plants and the environment, especially when they come into contact with bodies of water. |
| Avoid Excess Food Waste | Avoid sending water with excess food waste down the drain, as this can clog your greywater system and lead to unpleasant odors. |
| Regular Maintenance | Regularly clean and maintain your system to ensure it’s functioning optimally. |
| Monitor Water Quality | If using greywater for irrigation, ensure that the water quality is safe for plants by testing pH and nutrient levels periodically. |
| Choose the Right Filtration System | Match your greywater filtration system with your intended use. Some plants are more sensitive to residual soaps and nutrients than others, so selecting an appropriate system is key. |
Greywater-Safe Products
Using greywater-safe products can ensure that recycled water does not harm plants or the environment.
Many conventional soaps, detergents, and shampoos contain chemicals that can be detrimental when used in irrigation.
Here are some recommended greywater-safe products:
| Product | Description |
|---|---|
| Cleaning Soap | Opt for all-natural, biodegradable cleaning soaps that do not contain harsh chemicals or artificial fragrances. These soaps break down safely in the environment without harming soil health. |
| Dish Soap | Choose biodegradable dish soaps that are free from phosphates, chlorine, and antibacterial agents. These minimize contamination in greywater systems and are safe for soil. |
| Laundry Detergent | Opt for plant-based, fragrance-free detergents that do not contain boron, sodium, or synthetic surfactants, as these can be harmful to plants. |
| Shampoo and Conditioner | Use natural, sulfate-free shampoos and conditioners that avoid synthetic fragrances and preservatives, reducing the impact on greywater irrigation. |
Shop Greywater safe products
Final Thoughts on Greywater Systems
Installing a greywater system is a simple yet powerful way to save water, reduce costs, and live more sustainably.
Whether you’re in a tiny home or a traditional house, recycling water helps protect valuable resources and supports a more eco-friendly lifestyle.
If you’re looking for a practical way to lower your environmental impact, a greywater system is a smart investment.
With the right setup and proper maintenance, you’ll enjoy long-term savings and a greener, more self-sufficient home.
Frequently Asked Questions
Do I need a permit for a greywater system?
It depends on your location. Some areas require permits, while others have guidelines for safe use. Check local regulations before installing a system.
Is a greywater system safe for plants?
Yes, if you use biodegradable soaps and detergents. Avoid harsh chemicals, as they can harm soil and plants. A simple filter helps remove debris before reuse.
What is a greywater system?
A greywater system collects and reuses water from sinks, showers, and washing machines for irrigation or flushing toilets. It reduces water waste and is eco-friendly.
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