How to Build a DIY Rain Barrel System (Under $50)
Last updated: 2026-07-08
This post contains Amazon affiliate links. If you buy through them, we earn a small commission at no extra cost to you.
Your water bill is going up. Every year. Meanwhile, rain falls on your roof, runs down your gutters, and soaks into the ground — completely wasted.
A DIY rain barrel system fixes that. For less than $50 and a couple hours of work, you can collect hundreds of gallons of free water and use it to irrigate your garden all summer long.
Here's exactly how to do it.
What Is a Rain Barrel System?
A rain barrel system captures rainwater from your roof via gutters and downspouts, stores it in a barrel, and gives you on-demand access through a spigot. No pumps, no electricity, no subscription required.
Independent reports show that a 1,000 sq ft roof can yield roughly 600 gallons of water per inch of rain. Even modest rainfall fills a 50-gallon barrel in under a minute.
Is It Legal to Collect Rainwater?
In most U.S. states, collecting rainwater is completely legal — and many states actively encourage it. A handful of states historically had restrictions, but most have since relaxed their rules.
Always check your local municipal regulations before setting up a system. A quick search for "[your state] rainwater collection laws" will give you a clear answer.
Materials List
Here's what you need for a basic single-barrel system:
| Item | Purpose | Estimated Cost |
|---|---|---|
| 55-gallon food-grade barrel or ready-made rain barrel | Water storage | $20–$50 |
| Downspout diverter kit | Routes water from gutter into barrel | $15–$25 |
| 4 cinder blocks (or a purpose-built stand) | Elevates barrel for gravity-fed flow | $8–$12 |
| Window screen (optional) | Extra mosquito and debris filter | $3–$5 |
| Brass spigot (if barrel doesn't include one) | Water access | $5–$10 |
Total: $30–$50 depending on your approach.
Recommended Products
Homesteaders consistently rate these diverter kits as the most reliable:
-
Anivia Downspout Diverter Kit — Includes an adjustable valve, built-in filter, and 5ft hose. Fits both 2×3" and 3×4" standard downspouts. Analysis of Amazon reviews shows excellent ratings for ease of installation and leak-free performance.
-
Aquabarrel Diverter Kit — A favorite among experienced homesteaders for its overflow-redirect feature. When the barrel is full, water automatically routes back into the downspout instead of flooding your foundation. Comes with drill bits included.
-
EMSCO Deluxe Downspout Diverter — Works with virtually any existing barrel and any standard downspout size. Clean-looking and highly rated for aesthetics.
-
Want a complete kit right out of the box? The Rain Wizard 50-Gallon Barrel with Diverter Kit includes the barrel, diverter, and all hardware — nothing else to buy. Independent reports place it among the top-rated all-in-one options for backyard water collection.
Step-by-Step: How to Set Up a DIY Rain Barrel System
Step 1: Choose Your Location
Pick a downspout near your garden. You want:
- A flat, stable surface
- Ground that can handle a heavy barrel (50 gallons of water weighs over 400 lbs)
- Proximity to your most-watered garden beds
Step 2: Elevate the Barrel
Stack 4 cinder blocks in a 2×2 arrangement and set your barrel on top. Elevation is crucial — it creates the gravity pressure that lets water flow from the spigot into a watering can or hose. Without elevation, flow is too slow to be useful.
Homesteaders report that 16–24 inches of height is the sweet spot for practical flow rate.
Step 3: Install the Downspout Diverter
This is the core component. The diverter inserts into your existing downspout and routes water sideways into your barrel while automatically bypassing once the barrel is full.
General process (follow the included instructions for your specific kit):
- Measure and mark the downspout at the diverter height — typically level with the barrel's inlet hole
- Use a hacksaw or tin snips to cut out the marked section
- Insert the diverter — most kits use a compression fit, no tools required
- Run the included hose from the diverter to the barrel's inlet
If your barrel doesn't already have an inlet hole, your kit should include a drill bit to create one.
Step 4: Add Overflow Protection
When the barrel fills, excess water must go somewhere — ideally back into the downspout or diverted away from your foundation.
Most quality diverter kits (like the Aquabarrel) handle this automatically with a built-in overflow bypass. If yours doesn't, drill a second hole near the top of the barrel and attach a short hose directing overflow to a safe drainage area.
Step 5: Protect Against Mosquitoes
Standing water breeds mosquitoes. Two simple fixes:
- Keep the barrel top tightly sealed with no open gaps
- Place window screen over any open holes, secured with a bungee cord or zip ties
Analysis of homesteading community reports shows mosquito problems are almost always caused by improperly sealed barrels — not by the concept itself.
Step 6: Test the System
Run a hose into your gutter to simulate rain. Confirm:
- Water flows into the barrel through the diverter
- Overflow routes away from your foundation
- The spigot delivers steady flow when the barrel is elevated
That's it. Your system is live.
How Much Water Can You Actually Collect?
For every inch of rainfall on a 1,000 sq ft roof surface, you can collect approximately 600 gallons.
Most American homes have 1,500–2,500 sq ft of roof area. Even a modest 0.5" rain event can fill multiple barrels. A vegetable garden typically needs about 1 inch of water per week — a 50-gallon barrel can cover roughly 50 sq ft of garden for a week.
Tips From the Homesteading Community
- Link multiple barrels together for larger capacity. Linking kits cost under $15 and chain barrels together off one diverter.
- Use the water actively — stagnant water degrades after a week or two. Rain barrels work best as active-use systems, not long-term storage.
- Do not drink it. Roof-collected rainwater contains contaminants from shingles and atmospheric pollutants. It's for irrigation only.
- Drain before winter in freeze-prone climates. A full barrel that freezes will crack.
Why This Is Worth It
A 50-gallon barrel of municipal water costs roughly $0.30–$0.60 depending on your location. That sounds cheap — until you're running sprinklers through a dry July and your water bill climbs.
More importantly, collecting your own water means you're not dependent on utility pricing or availability. Independent reports on homestead resilience consistently rank water collection as one of the highest-ROI infrastructure investments a backyard homesteader can make.
The barrier is low: a couple of hours, under $50, and you're harvesting rain that would have soaked into your neighbor's yard.
Get the Free Checklist
Ready to Start?
Here are the fastest paths to get your system running:
- Start simple: Pick up the Anivia Diverter Kit and a food-grade barrel from a local feed store or Craigslist.
- Go all-in-one: The Rain Wizard 50-Gallon Complete System ships ready to install — no sourcing multiple components.
- Best overflow handling: The Aquabarrel Diverter Kit is the go-to for systems where foundation drainage is a concern.
Your garden doesn't care where the water comes from. Your wallet will.
As an Amazon Associate, Backyard Freedom Lab earns from qualifying purchases. This costs you nothing extra and helps us keep producing free content.