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Water from a rain barrel is best used for outdoor, non-potable jobs. Non-potable means water that is not intended for drinking.
For a basic roof-fed rain barrel, the simplest uses are watering ornamental plants, trees, shrubs, lawns, and indoor plants. You can also use it for jobs such as rinsing garden tools or other outdoor cleaning where drinking-quality water is not needed.
Do not assume rain barrel water is safe to drink, cook with, brush your teeth with, or use for other activities where you may swallow it. Roof runoff can pick up bird droppings, dirt, metals, roofing chemicals, and other contaminants before it reaches the barrel. The CDC recommends matching rainwater quality to its intended use and using treated drinking water when possible for drinking, cooking, washing produce, and watering plants you plan to eat.
Good Uses for Rain Barrel Water
A basic rain barrel works especially well when you can carry or move the water a short distance.
Water Flowers and Ornamental Plants
Flower beds, ornamental shrubs, and other plants you do not eat are among the most straightforward uses.
You can fill a watering can from the barrel spigot and carry the water where you need it. This also avoids depending on the small amount of pressure available from most rain barrels.
The CDC specifically lists watering plants you do not eat as a lower-risk use for collected rainwater.
Water Trees and Shrubs
Trees and larger shrubs can use a surprising amount of stored water.
Rather than sprinkling a little water over a large area, slowly apply the water around the plant's root zone. This lets more of it soak into the soil instead of running away.
A barrel can empty quickly when watering established trees, which is often useful when you want to make room before the next storm.
Water the Lawn
Rain barrel water can also be used on grass.
A watering can or short hose may work well. A normal lawn sprinkler may not.
Most rain barrels rely on gravity instead of a pump. The water pressure at the outlet is therefore much lower than normal household water pressure. Raising the barrel slightly can increase pressure, but the stand must safely support the full barrel.
Water is heavy. Do not put a full barrel on an unstable stack of blocks, loose soil, or a weak platform just to gain more pressure.
Water Indoor Plants
You can carry rain barrel water indoors for houseplants.
Keep in mind that untreated roof runoff is still non-potable water. Store and handle it separately from drinking water, and do not use containers that could later be mistaken for drinking-water containers.
Rinse Garden Tools and Outdoor Equipment
Rainwater can be useful for rinsing dirt from:
- Shovels and hoes
- Plant pots
- Wheelbarrows
- Outdoor furniture
- Other non-food garden equipment
CDC guidance also lists washing items that are not used for cooking or eating as a possible lower-risk use.
Wash a Vehicle
Roof runoff is sometimes used for vehicle washing. EPA materials have long listed vehicle washing among common outdoor rainwater uses.
Check local rules about where vehicle wash water is allowed to drain. Soap, oil, and dirt washed from a vehicle should not simply be sent wherever the rain barrel happens to be located.
Can You Use Rain Barrel Water on a Vegetable Garden?
This needs more care.
Water collected from a roof is not the same as clean drinking water. It can pick up bacteria from animals as well as chemicals from roofing, gutters, pipes, and storage materials. EPA also notes that these contaminants are important considerations when roof runoff is used around edible plants.
The CDC recommends using public tap water or bottled water when possible for watering plants you plan to eat.
That does not mean every rainwater system used around food crops is identical. Water quality depends on the collection surface, system design, maintenance, treatment, local conditions, and how the water is applied.
If edible-crop irrigation is an important part of your rainwater plan, treat it as a water-quality question rather than assuming that any barrel of roof runoff is suitable. Your local health or environmental authority can provide guidance appropriate to your area.
What Should You Not Do With Basic Rain Barrel Water?
A normal rain barrel is mainly a small outdoor water-storage system. It is not a drinking-water treatment system.
Unless you have a properly designed system for the intended use, avoid using untreated barrel water for:
- Drinking
- Cooking
- Making ice
- Brushing teeth
- Washing or rinsing food
- Filling pet drinking bowls
- Bathing
- Connecting directly to household drinking-water plumbing
Rainwater can look clear and still contain germs or chemicals. The CDC states that rainwater is not necessarily safe to drink without appropriate treatment and recommends regular testing when rainwater is used for drinking, cooking, or bathing.
Adding one small filter to the outlet does not automatically make the water potable. Potable means suitable for drinking.
Drinking-water use requires looking at the whole system: the roof and collection materials, debris control, first-flush management, storage, treatment, maintenance, current laboratory testing, and applicable local requirements.
Do Not Connect a Rain Barrel Directly to Drinking-Water Plumbing
Keep untreated rainwater separate from your home's potable water system.
A plumbing connection that allows rainwater to flow backward into drinking-water pipes can contaminate otherwise treated water. CDC guidance specifically recommends keeping collected rainwater from entering pipes carrying safe drinking water.
Using rainwater for toilets or other indoor non-potable uses is possible in some larger systems, but that is different from running a hose from a backyard barrel into the house. Indoor reuse can require treatment, backflow protection, dedicated piping, controls, permits, and other safeguards depending on local rules. EPA describes rain barrels mainly as simple outdoor-use systems, while larger cistern systems may be designed for more complex uses.
How Do You Get the Water Out of a Rain Barrel?
The easiest options are a watering can or a gravity-fed hose.
Watering Can
Place the can below the barrel spigot and open the valve.
Look closely at DIY rain barrel designs to verify airflow and overflow provisions around the storage vessel.
This method is simple, works with almost any barrel, and does not depend on much water pressure.
Short Garden Hose
A hose can work if the area you are watering is lower than the water level in the barrel.
Gravity creates the flow. As the barrel empties, pressure drops.
Long hoses, uphill runs, restrictive nozzles, and normal sprinklers may produce disappointing flow.
Drip Irrigation
A rain barrel can sometimes feed a small drip system, but the parts must work at very low pressure.
Many irrigation devices are designed for pressurized household water. Filters, pressure regulators, emitters, timers, and valves can all reduce the already-low flow from a barrel.
Check the operating requirements of the irrigation equipment before connecting it.
Pump
A pump can provide more flow or pressure when gravity is not enough.
That turns a simple rain barrel into a more complex system. The pump must be compatible with the available water volume, desired flow, required pressure, power source, connections, and possible debris in the water. Dry-run protection is also useful because a small barrel can empty quickly.
Any outdoor electrical equipment should be installed and powered in a way that is suitable for wet locations.
Use the Water Regularly
A rain barrel is generally more useful when water moves through it instead of sitting unused for long periods.
Using stored water also leaves room to capture the next rainfall.
Keep leaves and debris out of the barrel and maintain screens over openings. CDC guidance recommends screening rainwater systems against insects or emptying rain barrels at least every 10 days to help prevent mosquitoes from breeding.
If the barrel develops heavy sediment, odor, algae, or obvious contamination, do not simply keep adding new water indefinitely. Empty and clean the system as appropriate for its design.
A First-Flush Diverter Can Reduce Some Contamination
A first-flush diverter sends the first part of roof runoff away from the storage container.
That early runoff often carries more dust, bird waste, pollen, and other material that accumulated on the roof between storms. The CDC recommends considering first-flush diversion as one way to improve collected rainwater quality.
It does not sterilize the remaining water or make the barrel water automatically drinkable. It is one part of managing water quality.
What If You Have More Water Than You Can Use?
You do not need to find a household use for every gallon.
If the barrel needs to be emptied, release the water somewhere it can soak into the landscape without causing erosion, flooding a neighbor's property, or sending water back toward your house.
Possible locations include an appropriate planted area or rain garden.
Your barrel should also have a proper overflow route. Once the barrel is full, additional roof runoff needs somewhere safe to go. Avoid dumping overflow next to the foundation simply because that is where the downspout and barrel are located.
EPA identifies rain barrels and cisterns as ways to capture runoff for later irrigation and other non-potable uses while reducing immediate stormwater runoff.
Think About the Water Use Before Building a Bigger System
A single rain barrel is well suited to simple outdoor watering. If your goal grows beyond that, the system requirements change.
For example, supplying several garden zones may require more storage and better water distribution. Supplying toilets may require dedicated plumbing and treatment. Supplying drinking water requires a much more complete water-quality plan.
Start with the intended use and work backward:
- Decide what the water will be used for.
- Decide how much water that use requires.
- Check whether the collection surface is suitable.
- Provide debris and insect control.
- Choose storage that fits the available space.
- Make sure outlets, hoses, pumps, or irrigation parts are compatible.
- Provide a safe overflow route.
- Add treatment and testing when the intended use requires them.
- Check applicable local rules before connecting rainwater to building plumbing.
For many homes, there is no need to make the system complicated. Using barrel water on ornamental landscaping can save treated tap water while keeping the collection and distribution setup simple.
Frequently Asked Questions
What is the best thing to do with rain barrel water?
Watering flowers, ornamental plants, trees, shrubs, and lawns is usually the simplest use. These jobs do not require drinking-quality water and work well with a basic gravity-fed barrel.
Can I drink water straight from a rain barrel?
No. Do not assume roof runoff is safe to drink. Rainwater can contain germs and chemicals picked up from the air, roof, gutters, pipes, and storage system. Drinking-water use requires suitable collection, treatment, maintenance, testing, and compliance with applicable local requirements.
Can I use rain barrel water for my vegetable garden?
Roof runoff can contain contaminants, so edible crops need more caution than ornamental plants. The CDC recommends using public tap water or bottled water when possible for plants you plan to eat.
Can I attach a garden hose to a rain barrel?
Yes, if the barrel has a suitable hose connection. Expect much less pressure than you get from a household faucet. Short, downhill hose runs generally work better than long or uphill runs.
Can a rain barrel run a sprinkler?
Sometimes, but many normal sprinklers require more pressure and flow than gravity from a rain barrel can provide. A low-pressure irrigation setup or properly selected pump may be needed.
How long should water sit in a rain barrel?
It is better to use the water regularly and keep the system maintained. To help prevent mosquito breeding, the CDC recommends screening openings or emptying the barrel at least every 10 days.
What should I do when I cannot use all the water?
Release it slowly to a suitable landscape area where it can soak in safely, or route overflow to an appropriate drainage or infiltration area. Keep discharged water away from places where it could damage the foundation or cause erosion or flooding.
