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Drilling a rain barrel is usually a simple DIY job if the barrel is empty, stable, and made from a material that can be drilled safely. The most important step is choosing the hole size based on the fitting you plan to install. Do not guess from the pipe size alone.
For most plastic rain barrels, a hole saw gives the cleanest opening for a spigot, bulkhead fitting, overflow fitting, or barrel connector. Drill slowly, keep the tool straight, and remove rough plastic before installing the fitting.
What You Need to Drill a Rain Barrel
The exact tools depend on the fitting and barrel material. For a typical plastic rain barrel, you may need:
- A drill
- A hole saw or suitable drill bit
- The spigot, bulkhead fitting, or connector you plan to install
- A tape measure
- A marker
- A small file, utility knife, or deburring tool
- Safety glasses
- A scrap piece of wood for support, when practical
Check the fitting instructions before choosing the hole saw.
A fitting sold for a certain pipe size does not always need a hole of that same diameter. Threads, seals, and fitting bodies can be larger than the pipe they connect to.
Decide What the Hole Is For
Where you drill depends on what you are installing.
Spigot or Outlet
A spigot normally goes near the bottom of the barrel so you can use more of the stored water.
Do not place it directly against the bottom. Leave enough space for:
- The fitting and washer
- A hose connection
- Your hand or wrench, if needed
- Some sediment to settle below the outlet
Also check the outside of the barrel. A fitting that is too low may hit the ground or barrel stand.
Overflow Fitting
An overflow belongs near the upper part of the barrel.
It should be positioned so excess water can leave before the barrel overfills into an unwanted area. The overflow line should carry water to a suitable drainage point rather than dumping it next to a foundation.
Barrel-to-Barrel Connector
If you are connecting two rain barrels, the hole position matters on both barrels.
The fittings generally need to sit at compatible heights for the connection method you are using. Measure from the same reference point on each barrel before drilling.
Downspout or Diverter Connection
A downspout diverter may require a hole near the upper part of the barrel. Follow the diverter's installation requirements because the height of the barrel connection can affect how the system fills and returns excess water to the downspout.
Check the Barrel Before Drilling
Do not start drilling until you know what the barrel previously contained.
A reused barrel that held unknown chemicals, fuel, pesticides, or other hazardous materials should not be turned into a rainwater storage container just because it has been rinsed.
Also make sure the barrel is:
- Empty
- Clean enough to work on
- Not under pressure
- Stable
- Free of major cracks near the drilling point
For outdoor rainwater storage, plastic barrels are often made from polyethylene. These are usually straightforward to drill.
Metal barrels require different cutting tools and create sharp edges. If you are not comfortable drilling sheet metal safely, this is a good point to use a qualified installer or choose a container designed with ready-made ports.
How to Choose the Correct Hole Size
Choose the hole according to the fitting, not according to the size printed on a hose or pipe.
For example, a bulkhead fitting passes through the barrel wall and seals around the hole. The body of that fitting may need a larger opening than the pipe attached to it.
A bulkhead fitting is a fitting designed to pass through a tank or barrel wall while creating a sealed connection.
Before drilling:
- Read the fitting instructions.
- Find the required hole diameter.
- Compare that diameter with your hole saw.
- Check whether the fitting can be installed from the access you have.
Do not make the hole larger just to make installation easier. A hole that is too large may prevent the gasket from sealing properly.
If you do not have the fitting instructions, measure the part that must actually pass through the barrel wall and confirm the required opening with the fitting manufacturer before cutting.
How to Drill a Plastic Rain Barrel
1. Empty the Barrel
Drain all water from the barrel.
Working on an empty barrel makes it easier to control the drill and prevents plastic pieces from falling into stored water.
If possible, rinse the barrel before you work.
2. Set the Barrel on a Stable Surface
Keep the barrel from rolling or shifting.
You may find it easier to drill while the barrel is upright, especially when positioning a spigot or overflow. The important part is that the wall you are drilling does not move unexpectedly.
Do not hold a loose barrel with one hand while operating the drill with the other.
3. Mark the Center of the Hole
Use a tape measure and marker.
Check the location from both inside and outside when you can.
Make sure there is enough space around the hole for:
- The fitting flange
- Gaskets
- Nuts
- Hose connections
- Nearby ribs or curves in the barrel
Try to place a sealing fitting on a reasonably flat part of the barrel wall. Strong curves, molded seams, and raised ribs can make it harder for a gasket to seal.
4. Confirm the Hole Size Again
Place the fitting near the marked spot before drilling.
This is your last chance to catch a sizing or location mistake.
Check that the fitting will not interfere with the barrel base, lid, stand, downspout, or another fitting.
5. Fit the Correct Hole Saw
Install the required hole saw in your drill.
A hole saw cuts a round opening rather than removing the entire hole with one large drill bit.
Make sure the saw is secured correctly in the drill before starting.
6. Drill Slowly
Wear eye protection.
Place the center bit on your mark and hold the drill as straight as practical to the barrel wall.
Start slowly.
Let the cutting edge do the work rather than forcing it through the plastic. Excess pressure can make the saw grab, distort the barrel wall, or leave a rough opening.
Once the saw has cut through, release the trigger and remove the drill carefully.
7. Remove Plastic Shavings
Take out the cut plastic disk and any loose shavings.
Check both sides of the opening.
Small plastic curls or sharp edges can interfere with a gasket.
8. Smooth the Edge
Lightly remove burrs from the hole.
A burr is a rough or raised edge left after cutting.
Consider cutting a downspout for a rain barrel connection to verify cleaning access for sediment and odor control.
Do not aggressively enlarge the hole while smoothing it. You only want to remove material that could stop the fitting from sitting flat.
9. Install the Fitting
Follow the fitting manufacturer's instructions for gasket placement and tightening.
Many tank fittings use a rubber gasket to seal against the barrel wall. Installing the gasket on the wrong side or overtightening the fitting can cause leaks.
The fitting should normally be secure without badly crushing the gasket or bending the barrel wall.
How to Keep the Hole From Leaking
A clean hole helps, but the fitting itself creates the seal.
For a reliable connection:
- Use a fitting designed for tank or barrel walls.
- Drill the specified hole size.
- Choose a reasonably flat mounting area.
- Keep the gasket surface clean.
- Install washers and gaskets in the correct order.
- Avoid overtightening.
- Support attached pipes or hoses when their weight could pull on the fitting.
Do not assume that adding more sealant will fix a poorly sized hole.
Some fittings are designed to seal with their supplied gasket alone. Adding an unsuitable adhesive or sealant can make later maintenance harder and may not correct the underlying problem.
Can You Drill a Curved Part of a Rain Barrel?
Sometimes, but flatter areas are usually easier to seal.
A rigid fitting has flat sealing surfaces. On a strongly curved barrel wall, the fitting may not press evenly against its gasket.
Small fittings may tolerate gentle curves better than large fittings, but the fitting design matters.
Look for a flat molded section or an area with the least curvature when possible.
Drilling a Hole When You Cannot Reach Inside the Barrel
Some rain barrels have small lids or no useful access to the inside.
A standard bulkhead fitting often requires access to both sides of the barrel wall because a nut must be tightened from inside or outside.
If you cannot reach the inside, use a fitting specifically designed for installation from one side. Do not drop a standard nut into the barrel and hope to position it through a small opening.
Check the installation method before drilling the hole.
Common Rain Barrel Drilling Mistakes
Drilling Before Buying the Fitting
This is one of the easiest ways to end up with the wrong hole size.
Choose the fitting first.
Using the Pipe Size as the Hole Size
A fitting labeled for a certain pipe diameter may require a different mounting hole.
Always check the fitting's required opening.
Putting a Spigot Too Low
A low spigot may hit the ground or barrel stand and leave no room for a hose.
Measure the installed fitting, not just the center of the hole.
Drilling Through a Molded Rib
Raised ribs and seams may prevent a gasket from sitting flat.
Choose a smoother section when possible.
Pushing the Hole Saw Too Hard
Heavy pressure can make the drill catch or produce a rough opening.
Slow, controlled cutting is usually better.
Making a Small Hole Larger by Guessing
Repeatedly grinding or cutting away the opening can create an uneven edge that is difficult to seal.
Use the correct-size cutting tool from the start.
Overtightening the Fitting
More force does not always create a better seal.
Too much tightening can deform a plastic barrel, damage a gasket, or crack a fitting.
Test the Hole and Fitting Before Using the Barrel
After the fitting is installed, add a small amount of water before filling the barrel completely.
Watch the connection for leaks.
If you see water around the fitting:
- Drain the water below the fitting.
- Check the gasket position.
- Make sure the sealing surfaces are clean.
- Check whether the fitting is sitting squarely.
- Tighten only as recommended for that fitting.
If the hole is oversized, badly uneven, or cracked, simply tightening the fitting harder may make the problem worse.
Think About the Whole Rain Barrel Setup
The drilled hole is only one part of the system.
Before putting the barrel into service, also check:
- How rainwater enters the barrel
- How debris is kept out
- Where overflow water goes
- Whether openings are screened against mosquitoes
- Whether the barrel has a stable base
- Whether attached hoses put stress on the fittings
- How you will clean the barrel
- How the system will be protected in freezing weather
Stored rainwater is generally treated as non-potable unless the entire collection, treatment, testing, and maintenance system is designed for drinking-water use. Non-potable means water that is not being treated as drinking water.
A drilled fitting does not change the water's safety or intended use.
Frequently Asked Questions
What drill bit should I use for a rain barrel?
For a round fitting in a plastic rain barrel, a hole saw is usually the easiest way to make a clean opening. Use the diameter required by the fitting manufacturer rather than choosing the saw based only on the pipe size.
Can I use a regular drill bit instead of a hole saw?
A regular drill bit works well for small holes. Larger openings for spigots, bulkhead fittings, and overflows are usually easier to make cleanly with a hole saw. Avoid making a large opening by drilling many small holes around a circle because the edge may be difficult to seal.
How high should I drill the spigot hole?
Place it low enough to use most of the stored water but high enough to leave room for the fitting, hose, barrel stand, and some settled debris. The best height depends on the barrel and fitting.
Should I drill the rain barrel from the inside or outside?
Most plastic barrels can be drilled from the outside. Mark the location carefully and keep the drill straight. Check the inside first when possible so you do not drill into an internal feature or choose a location where the fitting nut cannot be reached.
Do I need silicone around a rain barrel fitting?
Not necessarily. Many tank fittings are designed to seal with a gasket. Use sealant only when it is suitable for the fitting, barrel material, and intended water use. Sealant should not be used to hide an incorrectly sized or damaged hole.
Can I drill a rain barrel while it is full?
It is better to empty the barrel first. A full barrel is heavy, water can escape as soon as the wall is opened, and plastic shavings can fall into the stored water.
Can I drill any plastic barrel for rainwater storage?
No. Make sure the barrel is structurally sound and that its previous contents were suitable for reuse. Do not use a container that held hazardous or unknown materials simply because it can be drilled and filled with rainwater.
What if I drilled the rain barrel hole too large?
Stop before installing or tightening the fitting aggressively. Whether the hole can be repaired depends on how oversized it is, the barrel material, and the fitting design. A larger compatible bulkhead fitting may sometimes be an option. A badly damaged or cracked wall may require replacing the barrel rather than relying on an uncertain patch.
