Project Overview
A coastal farming family needed a reliable water backup solution due to intermittent municipal supply issues. They requested a comprehensive rainwater harvesting system that could provide water for household use and irrigation during water outages.
The Requirements
The client needed:
- 5000L storage capacity for household backup
- Rainwater harvesting from roof runoff
- Filtration system for potable water use
- Automatic switching between municipal and tank water
- Irrigation supply for vegetable garden
- Coastal-resistant installation
Our Solution
Phase 1: Site Assessment & Design
We conducted a thorough assessment including:
- Roof area calculation (280m²)
- Average rainfall analysis for the area
- Household water usage audit
- Optimal tank location considering gravity feed
- Structural requirements for tank base
Phase 2: Installation
Tank Base Construction:
- Excavated and leveled site
- Created reinforced concrete slab (150mm thick)
- Installed proper drainage around base
- Ensured compliance with local regulations
Tank Installation:
- Positioned 5000L polyethylene tank
- Connected to downpipes from main roof
- Installed first-flush diverter system
- Added calmed inlet to prevent sediment disturbance
Plumbing Integration:
- Installed 3-stage filtration system (sediment, carbon, UV)
- Added pressure pump for consistent water pressure
- Connected automatic changeover valve
- Integrated with existing household plumbing
- Separate tap for irrigation supply
Phase 3: Testing & Commissioning
- Pressure testing of all connections
- Water quality testing
- Pump performance verification
- Changeover system testing
- Client training on system operation
The Results
System Performance:
- Collection: Can harvest up to 2000L from 25mm rain
- Filtration: Removes 99.9% of bacteria and sediment
- Backup: Provides 2-3 weeks of household water supply
- Irrigation: Dedicated supply for 200m² vegetable garden
- Switching: Automatic changeover in under 30 seconds
Key Features
Smart Design Elements:
- Gravity-fed first flush - automatically diverts dirty water
- Multi-stage filtration - ensures safe, clean water
- UV sterilization - eliminates harmful microorganisms
- Automatic changeover - seamless transition between supplies
- Low-level indicator - alerts when tank needs refilling
Coastal Considerations:
- UV-stabilized tank material
- Stainless steel fittings (corrosion-resistant)
- Secure tank anchoring for high winds
- Covered connections to prevent salt buildup
Client Benefits
The family now enjoys:
- 💧 Reliable backup water during municipal outages
- 💰 Reduced water bills through rainwater usage
- 🌱 Healthy vegetable garden with consistent irrigation
- 🏠 Peace of mind with automatic changeover
- 🌿 Sustainable living through rainwater harvesting
Technical Specifications
- Tank Capacity: 5000 liters
- Tank Material: Food-grade polyethylene (UV stabilized)
- Pump: 0.75HP stainless steel centrifugal pump
- Filtration: 3-stage (5 micron sediment, carbon block, UV)
- Piping: 25mm HDPE (UV protected)
- Collection Area: 280m² roof
- Estimated Annual Yield: 80,000 - 100,000 liters
Installation Timeline
- Design & Planning: 2 days
- Base Preparation: 2 days
- Tank Installation: 1 day
- Plumbing & Filtration: 2 days
- Testing & Commissioning: 1 day
- Total: 1 week
Client Testimonial
“Derwent Plumbing designed the perfect system for our needs. We’re now completely self-sufficient during water outages, and our garden has never looked better. The automatic switching means we don’t even notice when we switch between tank and municipal water. Excellent work!” - Thompson Family, South Coast
Need a water tank installation? We can help:
- Steve: 082 893 1742
- Goan: 076 198 3858