Step-by-Step Guide to Building a Rainwater Barrel

Collecting rainwater is an eco-friendly and cost-effective way to conserve water and reduce your utility bills. A rainwater barrel captures runoff from your roof, allowing you to reuse water for gardening, washing, or other non-potable household uses. Building your own rainwater barrel system is a rewarding DIY project that can be completed in a weekend with basic tools and materials. This comprehensive step-by-step guide will help you construct an efficient and functional rainwater barrel tailored to your needs.

Why Build a Rainwater Barrel?

Before diving into the construction process, it’s important to understand the benefits of harvesting rainwater:

• Water Conservation: Reduces reliance on municipal water supplies.
• Cost Savings: Lowers water bills by using free collected rainwater.
• Plant Health: Rainwater is softer and often better for plants than tap water.
• Environmental Impact: Decreases stormwater runoff, reducing pollution and erosion.
• Emergency Supply: Provides backup water during droughts or supply interruptions.

With these advantages in mind, let’s explore how to build your own rainwater barrel system.

Materials and Tools Needed

Materials

• Food-grade plastic barrel (50 to 100 gallons) or a large resin container
• Downspout diverter kit or flexible downspout extension
• Gutter downspout (if modification required)
• Bulkhead fitting with rubber washer (for spigot installation)
• Garden hose spigot or faucet
• Screen or mesh cover (to keep out debris and insects)
• Waterproof sealant or silicone caulk
• Gravel or concrete blocks (for elevating the barrel)
• Teflon tape (plumber’s tape)
• Optional: overflow hose and valve

Tools

• Drill with hole saw bits (size depends on fittings)
• Jigsaw or handsaw
• Screwdriver
• Measuring tape
• Marker or pencil
• Level
• Wrench or pliers

Step 1: Choose the Right Location

Selecting the right spot for your rainwater barrel is crucial for optimal performance and convenience.

Factors to Consider:

• Near a Downspout: Position the barrel directly beneath a downspout so it can easily collect water running off the roof.
• Elevated Surface: Find a stable, level area where you can raise the barrel 6–12 inches off the ground using blocks or gravel. Elevation improves water pressure when using the spigot.
• Accessibility: Ensure easy access to fill watering cans or connect hoses.
• Sun Exposure: Place in partial shade if possible to reduce algae growth inside the barrel.

Once you’ve identified a location, prepare the base by leveling it carefully.

Step 2: Prepare the Barrel

Most barrels sold for rainwater collection are food-grade plastic drums used for storage of liquids like food products. Avoid using barrels that previously contained chemicals.

Cleaning

Before installation, wash the barrel thoroughly with water and mild detergent. Rinse several times to remove any residues.

Modifications

You’ll need to make two main openings in the barrel:

1. Inlet Opening: Where water from the downspout enters.
2. Outlet Opening: For attaching the spigot near the bottom.

Use your drill with hole saw bits sized appropriately for your fittings.

Inlet Hole

Mark an opening near the top of one side of the barrel. This hole will accommodate either a downspout diverter pipe or flexible tubing from your gutter downspout.

Typical diameter: 2–3 inches depending on downspout size.

Cut carefully using a jigsaw if needed.

Outlet Hole

Mark a hole near the bottom of the barrel’s side where you will install a bulkhead fitting and spigot. This hole should fit snugly around your bulkhead fitting diameter (usually 1 inch).

Drill this hole cleanly to avoid leaks.

Step 3: Install Bulkhead Fitting and Spigot

The spigot allows easy access to stored water.

Bulkhead Fitting Installation

A bulkhead fitting is designed to create a watertight seal around penetrations through plastic containers.

1. Insert one half of the bulkhead fitting through the outlet hole from inside.
2. Place rubber washers on both sides of the hole.
3. Tighten the nut securely from outside while ensuring washers stay aligned.
4. Apply silicone caulk around edges for extra sealing.

Attach Spigot

Wrap Teflon tape around threads of your garden hose spigot, then screw it into the bulkhead fitting from outside.

Ensure it’s tight but avoid overtightening which can crack fittings.

Test for leaks by adding some water once assembly is complete.

Step 4: Configure Downspout Diverter or Connection

To divert roof runoff into your barrel:

Option A: Downspout Diverter Kit

Available at garden centers or hardware stores, diverters allow you to redirect water into your barrel while letting excess flow continue down original drainage during overflow events.

Installation generally involves:

1. Cutting downspout at specified height.
2. Attaching diverter housing with inlet going into barrel via flexible tubing.
3. Setting up overflow outlet back into downspout.

Diverters commonly include filters to block leaves and debris as well as screens.

Option B: Direct Flexible Pipe Connection

Alternatively, cut a hole in existing downspout above barrel inlet hole and attach flexible pipe leading directly into your barrel’s inlet opening. Secure with screws and seal gaps with waterproof sealant.

Step 5: Install Screen Cover

Prevent mosquitoes, debris, leaves, and dirt from contaminating your stored water by covering any openings exposed to air with fine mesh screen secured tightly over inlet holes.

Use a plastic lid with screened vent holes or custom-cut mesh attached with weatherproof adhesive or zip ties.

Step 6: Raise Your Barrel on Base

Elevate your rainwater barrel on concrete blocks, bricks, wooden pallets, or compacted gravel base. The elevation improves gravity-fed water pressure making it easier to fill watering cans or connect hoses directly to spigot without pumps.

Make sure base is level and stable under full weight of barrel (approximately 8 pounds per gallon when full).

Step 7: Set Up Overflow System (Optional but Recommended)

When your barrel fills beyond capacity during heavy rains, excess water needs safe release away from foundation areas:

1. Drill another hole near top side of barrel opposite inlet.
2. Install a bulkhead fitting connected to an overflow hose directing surplus water safely away from house.
3. Alternatively, leave open top covered with mesh screen if overflow flows naturally out of inlet pipe connection.

Step 8: Test Your System

After installation:

1. Slowly pour water into gutter above diverter/inlet.
2. Observe flow filling into barrel without leaking at fittings.
3. Check spigot function by opening it; ensure good flow rate.
4. Inspect all seals closely for drips; reseal as necessary.
5. Verify overflow directs excess safely away from structure.

Perform routine checks after storms and during seasons of heavy use.

Maintenance Tips for Rainwater Barrels

Proper maintenance ensures longevity and clean water supply:

• Regularly clean debris out of gutters feeding into barrels.
• Remove leaves and sediment build-up inside barrels annually.
• Replace mesh screens if torn or clogged.
• Drain barrels before winter if freezing temperatures occur in your region.
• Use non-toxic paints if you want to decorate barrels; avoid toxic coatings inside.
• Monitor for algae growth; keep barrels shaded if possible.

Conclusion

Building a rainwater barrel system is an effective way to conserve natural resources while supporting sustainable gardening practices at home. With basic materials and tools, you can craft a reliable setup that captures roof runoff efficiently, reducing dependence on municipal water supplies and lowering costs year-round. Careful planning, proper installation, and regular maintenance will ensure your rainwater harvesting system remains productive for many seasons ahead. Start collecting rain today—your plants and planet will thank you!