How to Collect and Use FREE Water

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Water is life. Life for humans, animals, and life for plants. Water is also costly, and in many places, scarce. Because of this, collecting and using FREE rainwater is an excellent idea. The practice of rainwater catchment is an ancient practice that has proven effective for thousands of years. 

The set-up can be simple or more complex, depending on your water needs.  Thankfully, there are no states in our country that prohibit rainwater harvesting. In the past, it was thought that this practice might interfere with the natural hydrologic system by removing water. However, this has been proven wrong, and people in every state have an equal opportunity to collect and use rainwater that falls on their property.

Let’s take a closer look at rainwater catchment, an economical, sustainable, and educational practice. 

There are numerous reasons to support a rainwater collection system, including:


Plants love rainwater. They prefer rainwater over groundwater and treated city water. City water generally contains chlorine and fluoride, which are not suitable for plants. Groundwater has a high pH and contains lots of salt and dissolved solids from agricultural use. These things build up in the soil over time and present as white chalky-looking deposits that reduce soil fertility. Rainwater is pure and unadulterated and helps to build up healthy soil over time. Also, it washes deposits from the soil that have accumulated and are not suitable for plants.


Do you have animals? Just like humans, animals need water to survive. Take a horse, for example. One horse will drink up to ten gallons of water each day. This can become a lot of water if you have more than one horse. If you keep chickens, goats, pigs, and other animals, your water needs will sharply increase. Many people have water collection set-ups that allow them to water their animals entirely on harvested water. 

Control runoff

If you live in an area that receives a lot of rain, it can actually become problematic. Perhaps you have experienced runoff issues such as flooding and erosion. These are not fun to deal with. Like a dam on a flood-prone river, a rainwater catchment system allows stormwater that would typically cause damage to be stored and reused for good.

Wildfire protection

Each year areas in the western part of the United States face the mounting threat of wildfires. With the added stress of global warming, this threat only increases. Having extra water on hand, especially in rural areas, can make a tremendous difference in saving homes and lives. Having excess water around is also beneficial in wildfire mitigation efforts. When restoring forestland, large amounts of material must be eliminated. This is accomplished by burning it off. For safety and to reduce the chance of additional fires, these piles must be thoroughly extinguished.


If you are like me and live in a place where water is scarce, saving what you can is vital. Many people are unaware of the amount of water that they waste. There is much pressure on city water systems where populations are growing, and waste is commonplace. Using water from a catchment system reminds us of this precious commodity that we often take for granted.


Water can be expensive, especially if you have high usage. Digging a well can be cost-prohibitive as well. However, setting up a water catchment system provides a way to harness mother nature’s water gift and reduce the expense. 

Sustainable living

Water, food, and shelter are the basic requirements needed for life. When we take advantage of the opportunity to harvest freshwater, we become more sustainable and control one of the most basic necessities for life.


There is no better way to teach children about the benefits of planning and saving than by allowing them to be part of your rainwater catchment system creation and maintenance. 

Basic rainwater collection system

The most basic catchment systems are easy for homeowners to install. These systems collect rainwater from a roof via downspouts, and a barrel or above-ground tank holds the water. These work well for garden use and even watering chickens or other animals. They are relatively inexpensive to install, and the only maintenance required is regular gutter cleaning and upkeep.

Using collected water inside your home

Indoor uses of collected water are becoming an increasingly popular practice. These systems are more complex, and with this comes a higher price. Eco-friendly homes may be equipped with rainwater systems for sinks, showers, washing machines, and toilets. Of course, filters are used in this system, as well as bacteria-resistant holding tanks. Water in these systems needs to be used frequently – if it sits for too long, bacteria can grow unless chemicals are used. It is also important that water does not come in contact with lead, heavy metals, or treated timber.

Potable water systems

Potable water catchment systems are the most expensive and complicated of all rainwater systems and must be set up cautiously and correctly. Many people who live off the grid use both snowmelt and rainwater for potable water. With that said, it is essential to note that there are numerous waterborne pathogens that can leave you very ill if they get into your holding tank. Birds and their excrement is also an issue as they carry pathogens. Someone who wants to use a water catchment and cistern storage system needs a complex system involving multiple filters and possibly chemical treatment.

How much water will I get from structure runoff?

Perhaps you think rainwater catchment is a good idea but not worth the effort. Here is a way to calculate how much water you can expect to harvest. 

  • 1 inch of water on one square foot of roof = 0.623 gallons of water
  • 10 inches of rain on 1000 square feet of roof = 6,230 gallons of water
  • 20 inches of rain on 2000 square feet of roof = 24,920 gallons of water

Look at how much rain you receive in the months that you wish to collect water. Calculate your roof area in square feet. Multiply these numbers together. Multiply this number by 0.623 to arrive at an average amount of water in gallons that you could harvest.

The best roof materials for rainwater harvesting

The best materials for roofs used to harvest rainwater include slate, aluminum, and galvanized iron. 

Rainwater harvest system installation is a rapidly expanding business

More and more companies and professionals offer services in rainwater catchment system installation. This is good news for homeowners who desire to install a more complex system than just a rain barrel. You must have the right filters, pipes, pumps, storage tanks, and monitors for complex systems. Using a professional service can help keep your water clean and you and your family safe.

Happy rainwater collection,

-Susan Patterson, CBHC and Master Gardener

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