Rainwater collection with IBC totes: a practical guide

We sell more rainwater-collection totes in spring than any other category. Most of them go to home gardeners and small farms; a few go to community gardens and block-clubs. Here's how to set one up so it works for years instead of becoming a mosquito breeding pond.

Calculate your roof catch first. A standard residential roof catches roughly 0.62 gallons of water per square foot per inch of rain. A 1,500 sq-ft roof in a 1" rain delivers about 930 gallons. That's three full IBC totes. If you have one tote, plan for it to fill in any moderate rain and design your overflow accordingly.

Site the tote on stable ground. Full, an IBC weighs 2,400 lb. Concrete pad is ideal; a level wood-rail platform works; soft ground does not. The tote needs to be slightly elevated (12-18") so you can fit a watering can or hose under the outlet valve.

Plumb the inlet through the top fill cap. Cut the top cap with a hole saw to fit your downspout reducer. We sell adapters that fit the 6" screw cap. Add a fine stainless mesh screen (24-mesh or finer) to keep mosquitoes out — not optional in mosquito country.

Add a first-flush diverter. The first 5-10 gallons off the roof in any rain carry the most contamination — bird droppings, accumulated dust, leaf bits. A simple PVC stand-pipe diverter discards that first flush before it reaches the tote. Major water-quality improvement for $20 in parts.

Plumb the overflow. If you're collecting from a roof bigger than your tote can hold, you need overflow drainage. Plumb a 2" pipe from the top of the tote to your storm drain or a soakaway pit. A tote that overflows uncontrollably will flood your foundation faster than you can run for the shovel.

Connect the outlet valve to a hose or drip line. The standard IBC outlet is S60×6 — we sell adapters to GHT (garden hose) and 1/2" or 3/4" drip-irrigation. For a gravity-fed drip line, plan on at least 24" of head pressure (tote elevated 24" above the line) for reliable flow.

Winterize. Empty the tote before first freeze. Water expands ~9% when it freezes; a full tote in a hard freeze can split the bottle. If you want year-round collection, get a heated jacket ($220) and an insulated hood for the top.

A typical residential rainwater rig with one IBC, downspout adapter, first-flush diverter, mesh screen, and outlet plumbing costs about $260 in parts plus the tote itself. It pays back in irrigation water savings inside a single growing season for most gardeners.