Rainwater Harvesting — FarmPal

Capture and store rainwater from roofs for garden irrigation and other non-potable uses.

Time Required
2-4 hours for basic barrel setup, half-day for more complex systems
Season
See notes

Benefits

  • •Free water for irrigation
  • •Reduces demand on municipal water
  • •Rainwater is naturally soft and good for plants
  • •Reduces stormwater runoff
  • •Provides backup water supply

Steps

1
Calculate Your Potential

Determine how much water your roof can capture. Formula: roof square footage × rainfall inches × 0.623 = gallons.

  • 💡 A 1,000 sq ft roof captures 623 gallons per inch of rain
  • 💡 Even small roofs can provide significant water
  • 💡 Start small you can always add more capacity
2
Choose Storage System

Options range from simple rain barrels to large cisterns. Consider space, budget, and intended use.

  • 💡 55-gallon drums are affordable starting point
  • 💡 IBC totes (275 gallons) offer more capacity economically
  • 💡 Underground cisterns are unobtrusive but more expensive
3
Install Collection System

Connect downspouts to storage containers through first-flush diverters and screens.

  • 💡 First-flush diverter removes initial dirty water
  • 💡 Screen prevents debris and mosquitoes
  • 💡 Overflow should direct away from foundation
4
Ensure Proper Overflow

All containers need overflow systems to handle heavy rains and prevent flooding.

  • 💡 Direct overflow to garden beds or rain garden
  • 💡 Overflow level should be below connection point
  • 💡 Consider daisy-chaining multiple barrels
5
Use and Maintain

Use gravity or pumps for distribution. Regular maintenance prevents mosquitoes and ensures water quality.

  • 💡 Empty barrels before winter in freezing climates
  • 💡 Clean screens and gutters regularly
  • 💡 Add barley straw or Bt dunks to prevent mosquitoes

Tools Needed

Rain barrels or tanks
Downspout diverter
Screen/filter for debris
Spigot and hose connections
First-flush diverter (recommended)
Overflow hose or pipe

⚠️ Safety

  • •Standing water breeds mosquitoes always screen and treat
  • •Not for drinking without extensive treatment
  • •Ensure stable placement full barrels are very heavy
  • •Children should not be able to access open containers
Seasonal Notes
Best to install in dry season. Empty and drain systems before hard freeze. Spring rain provides water reserves for summer garden.