Your Downspout Is Sitting on a Payday: The Beginner's Guide to Free Rainwater
Photo: U.S. Department of Agriculture, Public domain, via Wikimedia Commons
The Free Resource Falling on Your House
Here's a fun piece of math to ruin your day: a half inch of rain on a typical 1,000-square-foot roof sheds about 310 gallons of water. One storm. Multiply that by a summer's worth of pop-up thunderstorms, and you're watching hundreds of dollars of irrigation water splash down the driveway while your hose meter keeps ticking.
Rain barrels are the rare green upgrade that's cheap, legal in most places, and pays for itself in a season or two. Let's get you set up.
Step One: Check Your Local Rules (Yes, Really)
Before you buy anything, spend ten minutes on your state's water resources or environmental agency website. Rainwater collection is legal in most of the US, but the West — where water rights are famously fought over — has quirks.
- Colorado historically restricted rain barrels; as of 2016, residents may collect up to two barrels totaling 110 gallons.
- Utah allows up to 2,500 gallons stored, with some registration requirements.
- Nevada permits collection for household use under a state exemption.
- Washington and most other states are essentially wide open.
Some municipalities offer rebates that knock $25–$100 off a barrel's price. Search "rain barrel rebate" plus your city name — Austin, Seattle, and Portland all run programs.
What a Setup Actually Costs
The barrel itself ($80–$150 new; $30–$60 used). Many water utilities sell discounted barrels or host build-your-own workshops using repurposed food-grade drums. Facebook Marketplace and municipal sales are goldmines.
The hardware ($20–$40). A spigot, an overflow valve, and a downspout diverter. Get a screen on top — mosquitoes find standing water in under a week, and you do not want to trade a water bill for a bug nursery.
A platform (free–$40). Cinder blocks work fine. Elevating the barrel improves water pressure and makes filling a watering can easier.
Total: roughly $100–$200.
The Payback Math
A 55-gallon barrel fills after a single modest rainstorm. Garden watering accounts for a big chunk of summer household water use — often 30% or more — and a single barrel can meaningfully offset that during dry weeks. Most homeowners recoup their investment in one to three growing seasons, faster if your utility charges tiered summer rates.
Level Up: The Rain Garden
Once one barrel feels easy, consider a rain garden — a shallow, planted depression positioned to catch downspout or driveway runoff. Instead of sending stormwater (and whatever it picks up along the way) into the street drain, your yard soaks it slowly into the ground.
Plant it with natives that tolerate both feast and drought. Good picks across much of the US include coneflower, black-eyed Susan, swamp milkweed, switchgrass, and bee balm. Your state's native plant society or a local extension office will have a region-specific list — extension offices are criminally underrated and free.
Quick Setup Checklist
- Confirm your state and local rules.
- Pick a downspout near the garden you'll water.
- Install a diverter or cut the downspout to seat the barrel beneath it.
- Add a screen, a spigot, and an overflow hose pointed away from your foundation.
- Elevate, fill, and water.
That's it. The rain is going to fall either way — you might as well get your money's worth.
