DIY Rainwater Collection Systems


Rainwater harvesting through DIY collection systems is growing in popularity for environmentally conscious homeowners seeking self-sufficiency. With proper planning and installation, these systems can significantly reduce your water bills while also conserving natural resources. This comprehensive guide covers everything you need to know to successfully create your own efficient rainwater harvesting system.

Components of a DIY Rainwater Collection System

Several key components work together in a DIY rainwater harvesting system. Understanding the role each plays will help you plan and install your system properly.

Rooftop Catchment Area

Your rooftop surface serves as the catchment area – the larger, the better. Smooth, sloped surfaces with durable materials like galvanized steel, aluminum and slate are ideal. Ensure proper gutter maintenance around the roof perimeter to direct all rainfall into your system.

  • Smooth, sloped rooftops optimize catchment flow to gutters
  • Durable materials like galvanized steel, aluminum or slate recommended
  • Perform regular gutter cleaning and maintenance

Downspouts and Diverters

Seamless aluminum or galvanized steel downspouts transport rain from your rooftop gutters into the system setup below. Diverter valves then route flow into your rainwater storage tank.

  • Aluminum or galvanized steel downspouts recommended
  • Elbows, extensions and straps aid proper installation
  • Diverter valves easily direct flow when opened to storage tanks
DownspoutsAluminum, galvanized steelTransport rain from gutters to system
DivertersPVC, brass, stainless steelValves to route water flow into tanks

First Flush Device

First flush diverters capture and discard the first several gallons of runoff from your roof which contain most accumulated contaminants and debris. This helps provide cleaner water to your storage tank.

  • Captures first 15-25 gallons of roof runoff
  • Helps filter debris, contaminants and pollutants
  • Can be manual or automated

Rainwater Storage Tanks

Storage tanks provide reservoir space to stockpile your captured rainwater. Size your tank based on catchment area, rainfall averages, and intended water uses. Polyethylene or galvanized steel are common tank options.

  • Polyethylene or galvanized steel tanks recommended
  • Size based on catchment area, rainfall, and water usage
  • Placement on flat, solid foundation

Common Rainwater Storage Tank Options

Above GroundPolyethylene/PlasticLower cost, require space
Below GroundConcreteLonger lifespan, site excavation required
BladderPlastic/Synthetic RubberFlexible installation, lower capacity

Filtration System

Filtration and purification systems help remove sediment and contaminants from collected rainwater through methods like screening, filtration media, centrifugal separation and UV purification.

  • Pre-filtration captures debris early
  • Post-filtration removes contaminants
  • Filtration types:
    • Screen filters
    • Sand, coarse filters
    • Activated charcoal
    • Ultraviolet purification

Distribution System

Distribution refers to how your filtered rainwater reaches your intended end use, whether through gravity feed, manual transport or pressurized plumbing to outlets. Consider your requirements.

  • Gravity feed relies on water pressure
  • Pumps and pressure tanks can pressurize
  • Might need to integrate with existing plumbing

DIY Rainwater Collection System Installation

Installing your DIY rainwater harvesting system takes careful planning and preparation along with step-by-step installation tailored to your site. Use the following guidelines to properly implement your system.

Site Assessment and Planning

Careful planning ensures your system meets legal regulations in your area regarding rainwater harvesting for your intended uses. Thorough site assessment also determines best layout and sizing.

  • Evaluate site layout, dimensions and installation locations
  • Calculate ideal tank and catchment size based on water usage
  • Confirm compliance with local building codes

Tool and Material Preparation

Prefabricated kits require less custom construction, but you may source specialized components separately. Ensure you have all materials along with appropriate tools before starting.

  • Gather required plumbing parts: piping, fittings, valves
  • Water filters and accessories
  • Tools: screw guns, saws, shovels, measuring implements

Step-by-Step Installation Instructions

Follow this simplified step-by-step guide, but adjust to suit your unique setup. Always exercise safe practices during installation and get help lifting heavy components.

  1. Assemble primary water storage tanks on a solid, level base
  2. Install roof catchment gutters, down

spouts and first flush system

  1. Attach piping between downspouts and tank inlet
  2. Insert water filtration system with valves
  3. Attach distribution piping and outlets from tank
  4. Integrate overflow drainage line from tank
  5. Test water flow by simulated roof runoff or rainfall

Maintaining Your DIY Rainwater Harvesting System

Routine maintenance keeps your DIY rainwater system functioning properly for years. Prioritize inspections, cleaning schedules, treatment methods and usage guidelines.

Regular Inspection and Cleaning

Inspect entire system routinely, especially before wet season. Clear debris early and often from catchment and gutters. Check fittings, seals and filters. Clean out storage tanks annually.

  • Gutters and catchment area: Every 1-3 months
  • Tanks and lids: Annually
  • Filters and valves: Per manufacturer or every 3-6 months
  • Treatment system: According to guidelines

Water Quality Testing

Despite filtration methods, test harvested rainwater frequently to ensure it meets standards for non-potable uses according to local health regulations and your specific needs.

  • Color, cloudiness and particle inspection
  • Microbial testing for E. coli and other pathogens
  • pH levels, chemical composition


Constructing your own DIY rainwater collection system takes research, precise planning and methodical installation but pays dividends through water savings and sustainable living for years to come. Take advantage of free precipitation while also doing your part for environmental conservation through rainwater harvesting.

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