5 Most Common Uses of Rainwater in Landscape Irrigation

Rain barrel at the Ecological Solar House, Montreal. Photo: Benoït Rochon, Wikimedia Commons

By Emily Bartels

With the increasing water scarcity in some parts of the world, farmers and homeowners have developed new techniques to harvest rainwater for irrigation. Rainwater harvesting is not a new concept, as people have been collecting rainwater for thousands of years.

Collecting rainwater by any method helps farmers and homeowners to use it for irrigation when the groundwater becomes scarce. Over time, springs dry up and rivers become polluted, making water scarce and unsuitable for irrigation.

Rainwater is a pure and natural source of water. Therefore, harvesting rainwater for irrigation can become essential. It is especially useful in locations that experience scarcity of groundwater. Let’s explore the ways to use rainwater in landscape irrigation.

Rainwater Barrels

Rainwater barrels. Photo: Flickr

This method is the most common and the one many people are familiar with. It requires the installation of barrels under the gutter drain to collect rainwater from the roof. You can use a new or recycled barrel for the collection of rainwater.


  • Easy to apply to any place of residence.
  • Barrels are available at various home improvement stores.
  • Barrels do not take up much space, so they can fit in any area.


  • The capacity of a barrel is usually only 50 to 100 gallons (227 to 455 liters).
  • Due to limited capacity, you may need a large number of barrels.

Dry System

Dry system. Ill.:

This method is a type of rain barrel configuration, but involves more storage volume. Essentially, the collection line empties directly into the top of the tank, so it “dries up” after each rain event.


  • It can store large amounts of rainwater.
  • Ideal for climates where rains come as large storms.
  • May be cheaper to implement.
  • Less complicated system than a wet system, so easier to maintain.


  • The storage tank has to be located next to your house.

Wet System

Wet system. Ill.:

This method involves underground collection pipes that connect multiple downspouts to different channels. Rainwater fills the underground pipeline, and the water will rise into the vertical pipeline until it is pushed into the tank by water pressure. Underground and above-ground collection pipes must have a waterproof connection. Since it depends on water column pressure, the tank inlet has to be installed at a height lower than the lowest gutter.


  • A wet system can collect rainwater from the entire collection surface.
  • Ability to collect from multiple channels and downspouts.
  • The tank may be located far away from your home.


  • Is more expensive to install due to underground pipes.
  • There should be sufficient space between the gutter and the tank inlet.

Uses of Rainwater irrigation

Rainwater can be used for the irrigation of crops, gardens, farms, and landscapes. These are the most common uses of rainwater in landscape irrigation.

Lawn Irrigation

Photo: Pikist

There are lawns at homes, commercial complexes, parks, and resorts. Homeowners, resort owners, and business owners use collected rainwater for lawn irrigation. It is especially useful where the groundwater is low and cannot be used for regular garden irrigation. You can harvest rainwater in large containers during periods of rain and use it for lawn watering during periods of drought. Sprinkler irrigation systems are best for lawn irrigation, as they consume less water.

Watering Gardens

Homeowners and landscape owners also use rainwater for watering plants and shrubs in their gardens. As the cost of water increases, it is best to make use of rainwater for garden irrigation. Using rainwater can be highly useful for garden irrigation if you install an irrigation system that consumes low water levels. However, it is essential to set up a rainwater harvesting system in such as way to use rainwater for your garden plants.

Crop Irrigation

Irrigation pond. Photo: Wikimedia Commons

Crops need the highest amount of irrigation as they are grown in large quantities by farmers and agriculture businesses. In locations where water resources are scarce, rainwater harvesting can be a boon for farmers and agriculture. However, as farms and crops require large amounts of water, farmers will need to store rainwater in large ponds or reservoirs to use it later for irrigation of their fields.

This can be expensive for small farmers and agriculture businesses. Irrigating the farms with rainwater requires investing in rain harvesting and an irrigation system, but later it can save a lot of money and helps enhance the crop yields.

Compost Formation

Water is necessary for proper decomposition in the compost pile. Often people start a compost pile, then forget to water, which leads to improper compost formation. So, try to start the compost when rainwater is available, whether it is direct rain from the sky or harvested for garden irrigation.

Rainwater is also better than tap water for creating compost tea. 

Rinsing Vegetables in the Garden

If you have a vegetable garden, you’re aware that vegetables have dirt on them when you harvest them. You can use rainwater for rinsing the vegetables in the garden itself to remove most of the soil and leave it in the garden. Since rainwater is not necessarily potable, you’ll need to rinse them again with tap water in the kitchen before preparing them.

Water Conservation

Rainwater harvesting can help us conserve water in the areas where the ground water level is negligible or too low to pump out of the ground. In addition to irrigation, rainwater can be used for home use, industrial use and even for drinking after purification treatment. Also, rainwater harvesting is not limited to locations with scarce water resources. It can be used in any part of the world receiving rainfall for some months of the year.

Final Words

Rain is the primary source of fresh water on earth. It is good for irrigation, home use, and many other uses. Some countries use rainwater for drinking after treating it with various purification methods. Plants, crops, shrubs, and trees flourish better with rainwater than tap water, as rainwater contains all the natural minerals required for their growth. However, users need to invest in a rainwater harvesting system and low consumption irrigation equipment to make best use of this resource.

Author: Emily Bartels is a content writer at The Irrigation Shop.
She enjoys writing on various topics mainly associated with home improvement, gardening, technology and gadgets. 

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, will continue its mission of demystifying gardening and making it more accessible to all.

3 comments on “5 Most Common Uses of Rainwater in Landscape Irrigation

  1. Hi there!
    Do you know what solar powered pump I can use to run rainwater barrel through a soaker hose to maintain 20-25 PSI max?

  2. Long dry season and small urban gardens do not conform to rain water harvesting well. Too much of the limited garden space would be occupied by storage tanks to save enough water for the remainder of space through such long dry summers.

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