Whether you obtain your drinking water from the city supplied source or a ground source well, we have all become painfully aware of how much water we consume on a yearly basis. Drinking, bathing, cooking, and maintaining the lawn and garden have become a costly venture indeed. By choice or by necessity, more and more homeowners are using ground source well water. And, with rising utility costs, along with the general maintenance costs of well water, cisterns have become an increasingly popular option to support wells.
Ground source wells are an example of a technology literally thousands of years in the making. Simply put, whether in ancient Egypt or modern day Pennsylvania, a well is a hole dug deep enough in the ground to access the existing water table. Once the water table is hit, water begins filling the hole and becomes a semi-permanently accessible source.
Cisterns, like wells, were born thousands of years ago. They have been used throughout history, and typically served to harvest rainwater. There are alternate ways these containers were supplied, especially in modern times. Sometimes filled by hand or by truck, sometimes filled from an existing well, the collection of free water from rain and run off was most widely utilized.
Both cisterns and wells provide water, but function in different ways. Wells tap into the ground’s existing water source and pump that water to another location. Cisterns serve as a passive system, like a large storage container. The two items, while different, can function together to reduce both cost and consumption of precious well water.
Aside from serving as a means of collecting free water, and reducing burden on the well, cisterns serve another essential function — one that any well water user is all too familiar with; emergency water in the event of an extended power outage. Because wells require a pump to carry water from the source to the destination (your sink, bathtub, toilet, or garden hose), a power outage means that without an alternate energy source, water will not flow as needed.
Because Cisterns can be arranged to use gravity to push water to the required fixtures, they can function as an emergency back up water source in times of power outage or well failure. Cisterns still require being replenished as the existing supply of water is consumed and this presents a separate issue when well water is not available for an extended period of time.
Those who should consider supplementing an existing well with a cistern or cisterns, should contemplate the following questions:
- Is water pressure an issue?
- Does the well produce enough water for those times when demand is highest (think holidays when the whole family is over and showering one after another)
- Is the treatment of well water which may require filtration, softening, and purification becoming too costly, or burdensome?
- Is your existing well reliable or are their periods where the well does not have enough water to function properly?
- Is there enough room on site to house a cistern? (which come in a wide variety of styles and sizes)
Because cisterns can be filled with rain water, well water, or manually filled, the options are seemingly endless. Prior to installing a cistern, homework and calculations are essential. If rainwater is the intended source, then detailed calculations of historical rainfall data coupled with the square footage of the catchment area (your roof for example) are required to determine the volume of water the cistern should be expected to handle. Bear in mind, just two inches of rain can produce up to 1 gallon of water per square foot of catchment area.
As in all things, the use of cisterns as a supplement to existing wells is a decision to be made on a case by case basis. However, one can be confident when making such a decision that thousands of years of trial and error has made today’s wells and cisterns a “tried and true” means of providing water to our homes and buildings.
United States Geological Society; Howard Perlman. December 22, 2011. Department of the Interior February 18, 2012 http://ga.water.usgs.gov/edu/earthgwwells.html
S.E. Smith, “What is the Difference Between a Well and a Cistern?” WiseGeek. Ed. Bronwyn Harris. 2003-2012.February 16, 2012.
Woodson, Roger. Water Well Pumps and Systems Mini-Ref. New York, Audel Technical Series. February 7, 2012.