How to Harvest Water Using a Rainwater Cistern

A metal rainwater cistern next to a building.

Harvesting precipitation is a growing practice as individuals and families are looking to conserve water. Whether these efforts are motivated by saving money, a desire to be more environmentally friendly, or a mixture of the two, this practice is certainly something to consider. One useful method of water collection is a rainwater cistern. Below, learn exactly what a rainwater cistern is, why water harvesting is beneficial, and how to actually practice it at your own home using this tool.

Note: Check with your local and states laws before implementing this practice, as collecting rainwater is illegal in some areas.

Why Consider Water Harvesting?

The concept of water harvesting is a simple one: it revolves around collecting rainwater and reusing it in ways where traditionally regular water would be used. You may be wondering what the advantages are that makes this practice worth delving into. Here are a few, explained below.

The first advantage of water harvesting is that it has the capability to significantly reduce water bills, depending on where you live and how much precipitation you receive. Whether you harvest water at home or at a place of business, the ability to use collected water negates the need to use water from a faucet or a hose in many instances, significantly cutting back this particular utility bill.

Another advantage of this practice is that it’s good for the community. While the growing population of many cities and towns puts a strain on the amount of ground water used, some communities struggle to meet the demands for water, leading to a shortage. Using water that you’ve harvested helps the community conserve water.

Harvested water can be used for a variety of purposes such as flushing toilets, watering plants and gardens, washing cars, and so on. This makes it a versatile resource to put to work in and around your home to save you money and help the environment.

What Is a Water Cistern?

A green plastic rainwater cistern next to a building.

A water cistern is a large tank that has the capacity to fit around 20,000 gallons of water in a residential setting. These are much larger than rain barrels, which are another rain water collection option. Water cisterns have several key components to them. First, there is the water holding tank—also known as the cistern itself. This part of the mechanism collects and stores rainwater. The cover or lid of the tool keeps the tank airtight. Next, a leaf and mosquito screen is placed at the water inlet to keep debris and critters out of the tank. Finally, the overflow mechanism allows water to overflow via a directed pipe, potentially directing overflow fluid to somewhere like a rain garden.

Barrels typically hold around 55 gallons of water. Due to their large size, they are a bit more of an undertaking at your home than a run-of-the-mill rain barrel. However, these large tanks certainly have their advantages. Obviously, they let you store more water, and they do so for longer periods of time. These tanks also provide the potential to completely eliminate the use of a potable water irrigation system from your landscape. Finally, cisterns can be installed above or underground.

Collecting Water Using a Water Cistern

Rainwater falling off a metal roof.

You can begin collecting rainwater in a cistern at your home by following the tutorial below.

Size Your Cistern

First, you’ll want to determine what size cistern is right for your home. This depends on how much rainwater you want or can harvest, the amount of space you have available, and how much money you want to spend. Use either a tool designed to help you determine your ideal cistern size or have a design professional determine this for you.

Choose a Material

Cisterns can be made out of different materials. Determine whether a concrete, metal, polyethylene, plastic, or wooden cistern is right for your yard and home and purchase your cistern.

Pick Your Spot

Choose the best spot for your cistern. To do this, check your local building codes as there may be regulations that will help determine where your cistern should be placed or whether or not it requires a permit. The most cost-effective spot to place your cistern will be closest to the source point for the water to be stored. This means that a spot next to a downspout that collect roof runoff is best. Furthermore, place the cistern uphill from where the water will be used to avoid having to pump the water at the time of use.

Create a Foundation for the Cistern

Now, create a firm and level foundation location that your cistern will be placed on. If your tank will have a capacity of over 500 gallons, a concrete pad or compacted gravel foundation is a must. Your cistern will sit on this spot.

Install Your Overflow Pipe

Next, install your overflow pipe and ensure that it possesses the appropriate screen to prevent debris, birds, insects, and rodents from entering your tank.

Maintain the Cistern

Once your cistern is in place, you need to maintain it to ensure its optimal performance. Be sure to inspect the catchment area every six months to remove debris, deter algae growth, and clear any other obstructions from the surface of the mechanism.

Cisterns take a bit of work, but they’re worth the investment for the versatile use of harvested rain in your home. Follow these steps and tips to collect rainfall with your cistern to save money and help the community and environment alike.