If you’re considering adding a cistern to your home this post is a must read before you make any decisions. Cisterns are an excellent way to conserve water which is not only great for your neighborhood and city but also provides a huge savings to your water bill as utility rates are constantly increasing these days.
What is a Cistern?
A cistern is essentially a tank for storing water. These can be as simple as adding a couple rain barrels to your downspouts or as complex as a 5,000 gallon underground storage unit to supply a whole house. Cisterns have been used for thousands of years and date back to ancient civilizations such as the Romans, Greeks, and Egyptians. These early cisterns were often made of stone or lined with plaster and served as crucial water sources for households, agriculture, and public spaces.
Early cistern designs featured simple structures like pits or underground chambers that collected rainwater or water from nearby springs. Over time, advancements in engineering and architecture led to the development of more sophisticated designs, including rooftop catchment systems, underground vaults, and even large-scale cisterns built within fortresses and castles.
What’s the Difference Between a Well and a Cistern?
A well is a hole dug into the ground to tap into the water table and provide a source of water. Depending on the topography of your area you may have to dig only 30-40 feet like here in Florida before reaching the water table. Other areas may require wells to be dug hundreds or thousands of feet deep before reaching a water source.
A cistern, on the other hand, is a place to store water that you collect either from rainfall or springs. A cistern does not utilize an underground source of water like a well. Once collected that rainfall can be stored below or above ground and used for irrigation or, if treated properly, as potable water for drinking, cooking, and washing.
How to Properly Size a Cistern
Determining the appropriate size of your cistern is crucial to meet your water storage needs. Homes with more water intensive gardens or more occupants will require a larger cistern whereas a home with a garden consisting of low water native plants won’t require nearly as much storage.
Even if you want a huge cistern to provide water for the whole neighborhood there are some limitations beyond just budget. How big your cistern can be will largely depend on two factors.
- Roof area: Calculate the square footage of your roof to estimate the amount of rainwater you can collect.
- Average rainfall: Research historical rainfall data for your area to understand the water availability.
You can use this site to easily calculate your home’s potential with these two factors.
Materials for Residential Cisterns
When it comes to cistern materials, you have several options, each with its advantages and considerations.
- Polyethylene (Plastic): Cost-effective and lightweight, plastic cisterns are easy to install and resistant to corrosion making them a good DIY option. They come in various sizes and shapes, making them suitable for different spaces.
- Concrete: Durable and long-lasting, concrete cisterns can be customized to fit your specific requirements. You’ll likely need a pro to build and install these due to their weight and specialized construction techniques.
- Fiberglass: Known for their strength and resistance to corrosion, fiberglass cisterns are a reliable choice. They are lightweight and offer flexibility in size and shape.
Lifespan of Cisterns
- Plastic & Fiberglass: These options, can have an average lifespan of 20 to 30 years or more. Their longevity depends on the quality of the material, its exposure, and its resistance to UV degradation, impact, and temperature changes.
- Concrete: Concrete cisterns are known for their durability and longevity. With proper construction and maintenance, a well-built concrete cistern can last for several decades. The average lifespan of a concrete cistern ranges from 30 to 50 years or more.
Cistern Maintenance 101
Just like anything, cisterns need a little maintenance to perform long term. This will help you avoid clogged cisterns full of algae or sediment among all the other problems a residential cistern can encounter.
- Regular inspections: Check for cracks, leaks, or signs of damage. Check the tank itself (if you can) and any fittings. Repair any issues promptly to prevent further deterioration.
- Clean gutters and filters: Since most of the water in your cistern will be runoff from your roof it’s important to regularly remove debris, leaves, and sediment from gutters, downspouts, and filters to prevent clogging and maintain water quality.
- Water treatment: Consider implementing appropriate treatment methods, such as UV sterilization or chlorination, to ensure the water is safe for various uses.
- Winter preparation: For above ground cisterns in colder climates, protect them from freezing temperatures by insulating or draining before winter.
Congratulations you’re now one step closer to creating a sustainable water management system at your house, and the cistern is the heart of that system. With enough water stored safely your cistern can feed an entire garden throughout the growing season and beyond which means big time savings in water usage and money.
Founder & Editor-in-Chief
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
I got to see inside an early 1900s four square house here in Catonsville MD a few years ago during the annual open house tours. In the attic was what we think was a round cistern. It was about four feet tall and four feet across with various pipes. These old houses around here often have or had slate roofs, 12 inch roof joists, and true 2×6 inch wall studs. Could it have been a water cistern?