As an affiliate, we may earn a commission from qualifying purchases. We get commissions for purchases made through links on this website from Amazon and other third parties.
For most home rain barrels, opaque, UV-resistant high-density polyethylene (HDPE) plastic is the best material. It is light, does not rust, is easy to drill for fittings, and can handle years of outdoor use when made for water storage.
The best choice is usually a new or known-history HDPE barrel made for food or water contact. Avoid unknown used drums. A barrel that once held chemicals, fuel, pesticides, or other unsafe materials should not be reused for rainwater.
Material is only part of the decision. The barrel also needs a secure lid, screened inlet, overflow connection, useful outlet location, and protection from sunlight and freezing weather.
Why HDPE Plastic Works Well for Rain Barrels
HDPE is the thick plastic used for many drums, tanks, and water-storage containers. It works well for a basic rain barrel because it offers a good mix of durability and easy installation.
A suitable HDPE barrel can:
- Resist rust and corrosion
- Handle normal outdoor moisture
- Be moved more easily than a metal or concrete tank
- Accept bulkhead fittings, spigots, and overflow fittings
- Be cleaned with basic tools and supplies
- Last outdoors when the plastic includes good UV protection
A bulkhead fitting is a fitting that passes through the barrel wall and makes a sealed connection. It is often used for the spigot, drain, or overflow.
Plastic also makes DIY work simpler. You can usually drill the correct-size hole for a fitting without special metalworking tools.
The U.S. EPA has long used polyethylene drums in its basic rain-barrel guidance. EPA guidance also recommends limiting sunlight because sunlight can encourage algae growth in stored water.
Choose an Opaque Barrel, Not a Clear One
The color and light resistance of the barrel matter almost as much as the material.
Choose an opaque barrel that blocks sunlight. Dark or fully pigmented plastic is usually better than clear or translucent plastic.
Sunlight reaching stored water can encourage algae growth. An opaque barrel does not remove nutrients, germs, or other contaminants, but blocking light makes algae easier to control. EPA guidance recommends opaque storage rather than translucent materials for this reason.
Do not assume every dark plastic drum is suitable. You still need to know what the container was designed for and, if it is used, what it previously held.
New Water-Safe Plastic vs. Recycled Plastic Barrels
Reusing a drum can make sense, but its history matters.
A used barrel is a reasonable option when you can confirm that it held a suitable food product or another material that does not create a contamination concern. Clean it thoroughly before putting it into service.
Avoid barrels that previously contained:
- Fuel or oil
- Pesticides or herbicides
- Industrial chemicals
- Solvents
- Cleaning concentrates
- Unknown substances
Do not rely on smell or appearance to decide whether an unknown drum is safe. Some residues are difficult to remove.
A new barrel sold for water storage avoids much of this uncertainty.
What does "food-grade" mean?
Food-grade generally means the container or material is intended to be suitable for contact with food under specified conditions.
It does not mean that rainwater stored in the barrel becomes drinking water.
Roof runoff can collect dirt, bird droppings, microbes, metals, and other contaminants before it reaches the barrel. The CDC states that collected rainwater is not necessarily safe to drink and recommends appropriate treatment and testing when rainwater is used for drinking, cooking, or bathing.
How Other Rain Barrel Materials Compare
HDPE is usually the easiest choice, but it is not the only material available.
| Material | Main advantages | Main drawbacks | Best fit |
|---|---|---|---|
| HDPE plastic | Light, rust-free, easy to modify | Can weaken from poor UV protection and may be damaged by freezing | Most home rain barrels |
| Stainless steel | Strong and corrosion resistant | Heavy and harder to modify | Long-term systems where durability matters |
| Galvanized steel | Strong and rigid | Coating can eventually wear or corrode | Selected outdoor non-potable systems |
| Wood | Traditional appearance | Can dry, leak, rot, or need more upkeep | Decorative or specialty systems |
| Fiberglass | Strong and corrosion resistant | Harder for simple DIY modifications | Larger or purpose-built storage systems |
Stainless Steel
Stainless steel is strong and can provide excellent service when the grade, construction, fittings, and intended water use are appropriate.
It does not have the UV-degradation problem of plastic. It can also be very durable.
The drawbacks are practical. Stainless barrels are heavier, and adding an inlet, overflow, or spigot may require proper tools and fittings. For a simple barrel supplying a garden hose or watering can, HDPE is usually easier to work with.
Galvanized Steel
Galvanized steel has a zinc coating that protects the steel beneath it.
It can work for some rainwater systems, but damage, age, water chemistry, and long periods of wet storage can affect the coating. Once corrosion begins, maintenance becomes more important.
For a basic backyard barrel, plastic generally avoids these corrosion concerns.
Wood
Wooden rain barrels can look attractive, especially around older homes or gardens.
They also need more attention. Wood can shrink when dry, swell when wet, leak around joints, and eventually decay. Keeping insects and debris out can also be harder if the barrel was designed mainly for appearance rather than closed water storage.
Wood is usually a style choice rather than the simplest material for a low-maintenance rainwater system.
Fiberglass
Fiberglass is widely used for some larger tanks because it can be strong and corrosion resistant.
For a small DIY barrel, though, it provides fewer advantages. Cutting and modifying fiberglass requires care, and proper fittings are important. Purpose-built fiberglass tanks make more sense than trying to convert an unknown fiberglass container.
What to Look for in a Plastic Rain Barrel
Do not choose a barrel based on plastic type alone. Check the complete design.
A good rain barrel should have several features.
UV resistance
The plastic should be intended for outdoor exposure. A barrel that becomes brittle from sunlight can eventually crack.
Putting the barrel in partial shade can reduce sun exposure, but do not hide the barrel where you cannot inspect fittings or clean around it.
Opaque walls
Planning around practical considerations for there any non-toxic rain barrels available helps verify stored supply required between realistic refill opportunities.
Hold light up to the empty barrel if practical. A storage container that lets a large amount of light through may be more prone to algae growth.
A removable or accessible lid
You need some way to inspect and clean the inside.
The opening should still be secured against children, animals, debris, and insects.
A screened inlet
Rainwater coming from the downspout should pass through an insect-resistant screen where appropriate.
CDC guidance recommends screening rain-barrel openings to help keep mosquitoes out.
A proper overflow
A full barrel needs somewhere safe to send extra water.
The overflow should carry water away without flooding the foundation, eroding soil, or pouring directly beside the barrel base.
An overflow fitting should also be large enough to handle the water entering during heavy rain. A tiny overflow can become the weak point even when the barrel itself is large enough.
A strong fitting area
The wall around the spigot and overflow needs to support the fitting without bending badly.
Use fittings designed for the barrel wall thickness. Do not keep tightening a leaking plastic fitting until the barrel wall deforms. The leak may come from the wrong gasket, hole size, or fitting type.
Does Barrel Color Matter?
Yes, but mainly because of light.
Black, dark green, brown, blue, or another opaque color can work. The exact color is less important than whether the wall blocks sunlight and the plastic is made for outdoor exposure.
A light-colored barrel can also work if it is fully opaque.
Do not paint an unsuitable clear barrel and assume it is now equal to a purpose-built outdoor tank. Paint may peel, scratch, or fail to protect plastic that was never designed for long-term outdoor exposure.
What Material Is Best in Freezing Climates?
HDPE can still be a good choice, but water left inside the barrel can freeze and expand.
Do not assume a flexible-looking plastic barrel can safely hold a full load of frozen water. Ice can damage the barrel, spigot, valves, hoses, and fittings.
If freezing weather is expected, follow the barrel manufacturer's winter-storage guidance. Many simple systems need to be drained, disconnected, or otherwise protected before hard freezes.
Metal barrels are not immune to freeze damage either. Changing the tank material does not remove the need for winter planning.
Is HDPE Best for Drinking-Water Storage?
A normal garden rain barrel should not be treated as a drinking-water system.
If collected rainwater may be used for drinking, cooking, brushing teeth, or another use where water could be swallowed, the requirements become much stricter. The storage material should be appropriate for potable water use, and every part of the system matters. Potable means water intended to be safe for drinking.
The roof, gutters, collection piping, first-flush system, storage tank, treatment equipment, plumbing, maintenance, and water testing all affect safety.
A first-flush diverter sends some of the first roof runoff from a storm away from the storage tank. This water often carries a higher load of material washed from the roof. It can improve collected-water quality, but it does not make rainwater potable by itself.
CDC recommends regular testing for germs and chemicals when collected rainwater is used for drinking, cooking, or bathing and advises checking with the local health department about suitable testing and treatment.
For a potable system, use storage and plumbing components specifically suitable for that application and follow current local health and plumbing requirements. Some applications use components certified to standards such as NSF/ANSI 61, depending on the system and jurisdiction. A qualified water-treatment or plumbing professional may be appropriate for a household drinking-water setup.
The Best Choice for Most Homes
For a rain barrel used to water a lawn, ornamental garden, or similar outdoor area, start with an opaque, outdoor-rated HDPE barrel with a known history and suitable water-contact materials.
Then check the rest of the system. A good barrel still needs:
- A stable, level base
- A screened inlet
- A secure top
- An adequate overflow
- Leak-free bulkhead fittings
- A usable spigot height
- Regular cleaning and inspection
- Freeze protection where needed
Remember that water is heavy. Do not place a full barrel on an improvised stand, deck, balcony, or other structure unless you know it can safely carry the loaded weight.
Choosing the right material gives you a durable container. Choosing the right connections, location, and maintenance plan makes it a useful rainwater system.
Frequently Asked Questions
Is plastic or metal better for a rain barrel?
Plastic HDPE is usually better for a typical home rain barrel because it does not rust, is relatively light, and is easy to fit with a spigot and overflow. Metal may make sense when strength or a particular installation calls for it, but it can be heavier and may require more care around corrosion and fittings.
What type of plastic is best for rain barrels?
HDPE, or high-density polyethylene, is a strong choice. Look for an opaque barrel designed for outdoor use and suitable for its intended water-storage application. UV resistance is important if the barrel will remain outside.
Can I use a clear plastic barrel for rainwater?
It is better to use an opaque barrel. Light entering the water can encourage algae growth. A clear or highly translucent container usually needs more protection from sunlight than a purpose-built opaque rain barrel.
Is a food-grade barrel safe for drinking rainwater?
Not by itself. A food-grade barrel only addresses part of the storage question. Roof runoff may contain germs and chemicals, so drinking-water use requires suitable collection, treatment, regular testing, maintenance, and compliance with applicable local requirements.
Can I turn any 55-gallon drum into a rain barrel?
No. You should know what the drum previously contained and whether its material is suitable for your intended use. Do not use an unknown drum or one that held fuel, pesticides, hazardous chemicals, or other substances that could leave unsafe residues.
Do black rain barrels get too hot?
Dark barrels can warm in direct sun, but blocking light is useful for limiting algae growth. When possible, place the barrel where it receives less intense sun while still allowing easy inspection and maintenance. Make sure the barrel itself is rated for outdoor exposure.
Will a plastic rain barrel crack in winter?
It can. Water expands when it freezes and may damage the barrel, spigot, valve, or other fittings. Follow the barrel manufacturer's winter instructions and drain or protect the system when required for your climate.
