How to Build a Rain Water Harvesting System with IBC Totes

Why IBC Totes Make the Best Rain Barrels

Traditional rain barrels hold 50-60 gallons. A single used IBC tote holds 275 gallons — nearly five times the capacity at a fraction of the per-gallon cost. With a standard 40" x 48" footprint, an IBC fits in most backyard spaces, alongside a garage, or behind an outbuilding. And because used IBCs are readily available at $60-$120, the cost-per-gallon of storage is dramatically lower than purpose-built rainwater tanks.

For homesteaders, small farms, community gardens, and suburban gardeners, IBC totes represent the most practical and affordable path to serious rainwater collection.

What You'll Need

Materials

•1x used IBC tote (food-grade recommended if watering edible crops)

•1x first-flush diverter (sized for your downspout)

•1x fine mesh inlet screen (stainless steel, 1mm mesh)

•1x overflow fitting (3/4" bulkhead fitting with barbed connector)

•1x garden hose spigot adapter (2" to 3/4" reducer with ball valve)

•UV-resistant paint or IBC cover/wrap

•PVC pipe and fittings for downspout connection

•Teflon tape and silicone sealant

Tools

•Hole saw (2" and 3/4")

•Adjustable wrench

•Level

•Cinder blocks or pallet (for elevation)

Step 1: Prepare the IBC

Start by thoroughly cleaning the IBC with a diluted bleach solution (1 tablespoon per gallon) and rinsing three times. If the IBC previously held food-grade substances, a simple triple-rinse with water is sufficient.

Important: If the IBC held any chemical, solvent, or non-food substance, do not use it for watering edible crops. Use it for landscape irrigation, livestock watering, or fire suppression instead.

Cut a 6" opening in the top of the IBC for the inlet screen. The best location is directly below where your downspout will connect. Use a jigsaw or reciprocating saw with a fine-tooth blade designed for plastic.

Step 2: UV Protection

HDPE degrades in direct sunlight. If your IBC will be exposed to UV, you must protect it. Options include:

•Painting the bottle with UV-resistant exterior latex paint (light colors recommended)

•Wrapping with a UV-resistant tarp or commercial IBC cover

•Building a simple shade structure

•Positioning where the IBC receives minimal direct afternoon sun

Skip this step and you'll see yellowing and embrittlement within 12-18 months.

Step 3: Elevation

Elevate the IBC on a stable, level platform to provide gravity-fed water pressure. Each foot of elevation provides approximately 0.43 PSI of pressure. For basic garden watering with a hose, 2-3 feet of elevation is sufficient.

Options: Stacked cinder blocks (the most common), a reinforced wooden platform, or the IBC's own steel pallet placed on a compacted gravel pad.

Weight warning: A full 275-gallon IBC weighs approximately 2,400 pounds. Your platform must support this weight on potentially soft ground. A 4" gravel pad (at least 4' x 5') is recommended under any platform.

Step 4: Install the First-Flush Diverter

The first-flush diverter is the single most important component of your system. When rain begins, the first 10-20 gallons of water running off your roof carry the highest concentration of bird droppings, dust, pollen, leaf tannins, and other contaminants. The first-flush diverter captures and diverts this initial flow, allowing only cleaner water to enter your storage tank.

Install the diverter between your downspout and the IBC inlet. Size it for approximately 1 gallon per 100 square feet of roof catchment area. Most residential setups use a 3" PVC pipe, 4-6 feet long, with a ball valve at the bottom for draining.

Step 5: Overflow Management

When your IBC is full, additional rainfall must go somewhere. Without a proper overflow, water will back up into your downspout, potentially causing roof damage or flooding near your foundation.

Install a 3/4" or 1" bulkhead fitting near the top of the IBC (within 3" of the fill line). Connect this to a hose or pipe that directs overflow to a garden bed, rain garden, dry well, or storm drain.

Step 6: Multi-Tank Linking (Optional)

Need more capacity? Link multiple IBCs together using the existing 2" discharge valves. Connect the valves at the bottom of adjacent tanks using a short section of 2" hose or PVC pipe. Water will naturally equalize between linked tanks.

For optimal flow, position linked tanks at the same elevation. You can link up to 4 tanks (1,100 gallons) in a straight line before flow resistance becomes a factor.

Maintenance

•Clean the inlet screen monthly during the collection season

•Drain and flush the first-flush diverter after every significant rain event

•Drain the system completely before freezing weather if you're in a freeze zone

•Inspect the IBC annually for UV degradation, leaks, and algae growth

•Add 1/4 teaspoon of unscented bleach per 275 gallons monthly to prevent algae (if not watering edible crops)

How Much Water Can You Collect?

The formula is simple: Catchment area (sq ft) x Rainfall (inches) x 0.623 = Gallons collected

For a 1,500 square foot roof section receiving 1 inch of rain: 1,500 x 1 x 0.623 = 934 gallons. That's more than three IBC totes' worth from a single inch of rain.

The average U.S. home can collect 30,000-50,000 gallons of rainwater per year. Even capturing a fraction of that with a single IBC tote can significantly reduce municipal water use for irrigation.

Where to Get the Right IBC

We sell food-grade and industrial-grade used IBCs specifically suited for rainwater harvesting. Our custom solutions team can even pre-modify your IBC with inlet screens, overflow fittings, and UV wrapping before delivery.

Request a quote for rain harvesting IBCs.