Field-TestedIntermediate · 3 hours

Building a Rain Barrel System

Collect hundreds of gallons from your roof for gardens, flushing and (with treatment) drinking.

Question 1

The goal

Capture roof runoff safely and store it for non-drinking use or later treatment.

Question 2

Question 3

Material	Household	Wilderness	Urban / scavenged
Barrel	Large trash can	Tarp	Food-processing plants, car washes (used food-grade)

Question 4

1
Check local rules — some places regulate rainwater collection.
2
Calculate yield: roof area (sq ft) × rain (in) × 0.62 = gallons. 1,000 sq ft and 1 in of rain = 620 gallons.
3
Level a base of cinder blocks 12–18 in (30–45 cm) high next to a downspout for gravity pressure.
4
Drill a hole near the bottom and install the spigot with a bulkhead fitting and sealant.
5
Cut an inlet in the lid and cover it with fine mesh to keep out mosquitoes and leaves.
6
Add an overflow outlet near the top, routed away from the foundation.
7
Install a diverter on the downspout and connect it to the inlet.
8
Use a first-flush diverter or discard the first few gallons of each rain — roofs collect bird droppings and dust.
9
Keep the lid sealed; check monthly for mosquito larvae.
10
Treat before drinking: filter, then boil or disinfect.

Question 5

Rain is nearly pure when it falls, but roofs add bacteria, metals and debris. Darkness and sealing prevent algae and mosquito breeding.

Question 6

Question 7

The barrel fills after rain, overflows away from the house and has no mosquito larvae.

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