Tiny House Rainwater Collection
Rainwater collection for tiny houses offers an eco-friendly, cost-effective solution to water needs while promoting self-sufficiency. Whether you’re living off-grid or simply want to reduce your environmental footprint, a properly designed rainwater harvesting system can provide water for washing, showering, and even drinking. This guide will walk you through everything you need to know about setting up an efficient rainwater collection system for your tiny home.
Benefits of Rainwater Collection for Tiny Houses
Before diving into the how-to, it’s important to understand why rainwater collection is particularly beneficial for tiny homes:
1. Sustainability – Reduces dependence on municipal water supplies
2. Cost savings – Lowers or eliminates water bills
3. Self-sufficiency – Provides water independence, especially for off-grid living
4. Environmental impact – Reduces stormwater runoff and erosion
5. Adaptability – Can be scaled to fit the limited space of tiny homes
6. Water quality – Rainwater is naturally soft and free from many contaminants
Materials and Components Needed
To build a complete tiny house rainwater collection system, you’ll need:
1. Roof catchment area (your tiny house roof)
2. Gutters and downspouts
3. Pre-filtration system (leaf guards, first-flush diverters)
4. Storage tank(s)
5. Pump system
6. Post-filtration components
7. Plumbing connections
8. Optional: UV sterilizer (if using for drinking water)
9. Overflow management system
10. Water level indicator
Planning Your System
Calculating Your Water Needs
Before purchasing components, determine your daily water usage:
1. Average person uses 50-100 gallons per day in a conventional home
2. Tiny house dwellers typically use 5-15 gallons per day with conservation measures
3. List all water uses: drinking, cooking, bathing, laundry, dishes, etc.
4. Calculate your expected daily, weekly, and monthly usage
Assessing Your Collection Potential
To calculate how much water you can collect:
1. Measure your roof’s square footage (length × width)
2. Use the formula: 0.623 gallons × roof square footage × inches of rainfall
3. For example, a 200 sq ft tiny house roof can collect approximately 125 gallons from 1 inch of rainfall
4. Research average rainfall in your area to estimate monthly collection potential
Setting Up Your Rainwater Collection System
Step 1: Install Gutters and Downspouts
1. Choose gutters sized appropriately for your tiny house (typically 4-5 inches)
2. Ensure gutters have a slight slope (1/4 inch per 10 feet) toward downspouts
3. Install downspouts at the lowest points of your gutters
4. Direct downspouts toward your planned storage location
5. Use seamless gutters if possible to prevent leaks
Step 2: Pre-Filtration Setup
Pre-filtration is crucial for maintaining water quality:
1. Install leaf guards or screens over gutters to prevent large debris
2. Add a first-flush diverter to redirect the initial runoff containing the most contaminants
3. Consider a roof washer or pre-filter box before water enters storage
4. For tiny houses, compact pre-filter systems are available that combine these functions
Step 3: Storage Tank Installation
1. Choose appropriate tank size based on your calculations and available space
2. Select tank material: food-grade plastic, fiberglass, concrete, or metal
3. Place tank on a level, stable foundation
4. Position tank to receive water from downspouts
5. Install an overflow outlet that directs excess water away from your tiny house foundation
6. Consider multiple smaller tanks instead of one large tank for better space utilization
7. For tiny houses, look into slim-profile or custom-shaped tanks designed for limited spaces
Step 4: Pump and Pressure System
To use collected rainwater throughout your tiny house:
1. Install a small pump system (12V pumps work well for off-grid tiny houses)
2. Add a pressure tank if desired for consistent water pressure
3. Connect pump to a power source (solar, battery, or grid)
4. Install necessary plumbing to connect the pump to your tiny house water system
5. Consider a float switch to automatically turn the pump on/off based on water level
Step 5: Filtration and Purification
For safe water use:
1. Install a sediment filter to remove particles
2. Add an activated carbon filter to improve taste and remove chemicals
3. Consider a ceramic filter for biological contaminants
4. For drinking water, add UV sterilization or reverse osmosis filtration
5. Ensure filters are accessible for regular maintenance
Maintenance and Considerations
Regular Maintenance Tasks
1. Clean gutters and pre-filters seasonally
2. Inspect roof for contaminants (bird droppings, debris)
3. Check and clean filters according to manufacturer recommendations
4. Test water quality periodically, especially if used for drinking
5. Drain and clean storage tanks annually
6. Inspect for leaks or damage to system components
Special Considerations for Tiny Houses
1. Weight considerations: Full water tanks are heavy – ensure your foundation can support them
2. Space constraints: Consider vertical storage options or underground tanks
3. Mobility: For mobile tiny houses, design a system that can be easily disconnected
4. Freeze protection: Insulate components in cold climates or design for seasonal use
5. Local regulations: Check local codes regarding rainwater harvesting
Frequently Asked Questions
Is rainwater safe to drink?
Rainwater can be safe to drink with proper filtration and purification. At minimum, you’ll need sediment filtration, carbon filtration, and UV sterilization or other disinfection method. Regular testing is recommended if using rainwater for drinking purposes.
How much does a tiny house rainwater collection system cost?
Basic systems start around $500-1,000, while comprehensive systems with advanced filtration can cost $2,000-5,000. The exact cost depends on your water needs, system complexity, and component quality.
What if I live in an area with seasonal rainfall?
In areas with seasonal rainfall, you’ll need to size your storage tanks to capture enough water during rainy periods to last through dry seasons. Alternatively, plan for a backup water source such as delivered water or a well.
Do I need special insurance for using rainwater in my tiny house?
Some insurance policies may have specific requirements or exclusions for alternative water systems. Check with your insurance provider and consider adding specific coverage for your rainwater harvesting system.
Can I use rainwater for all my water needs?
Yes, with proper filtration and adequate storage, rainwater can meet all your water needs. Many tiny house dwellers successfully use 100% rainwater for washing, showering, and drinking, especially when employing water conservation practices.
By implementing a well-designed rainwater collection system, your tiny house can become more self-sufficient while reducing environmental impact. The initial investment in components and setup will pay dividends through water independence and sustainability for years to come.