Bore water refers to groundwater accessed by drilling a narrow shaft into the earth. This water is sourced from underground geological formations, not surface bodies like rivers or lakes. Many properties, particularly in rural or remote areas, use this resource as a self-sufficient alternative to a municipal supply system. Assessing its suitability and safety requires understanding its origin and infrastructure.
Defining Bore Water and Its Source
Bore water is groundwater originating from rainfall that percolates downward through soil and rock layers. This water is stored in saturated underground zones called aquifers, which are formations of permeable rock, sand, or gravel. The top level of this saturated zone is known as the water table.
The quality of bore water depends heavily on the type of aquifer. Shallow, unconfined aquifers are closer to the surface and are often susceptible to contamination from human activities. Conversely, water from deep, confined aquifers is generally protected by thick layers of rock or clay, acting as a natural filter. However, deep water may still contain elevated concentrations of naturally occurring minerals or chemicals, depending on the local geology.
Accessing the Water: The Borehole Structure
Accessing groundwater requires constructing a borehole, a vertical shaft drilled into the earth using specialized equipment. Once the aquifer is reached, the hole’s integrity must be maintained to ensure a reliable supply and prevent collapse. Structural stability is provided by a permanent lining called casing, typically a steel or plastic pipe installed for the length of the shaft.
The casing includes a well screen or perforated section at the aquifer depth, allowing water to flow into the well while preventing large sediment entry. A gravel pack may be placed between the casing and the drilled wall for additional filtration and support. To retrieve the water, a submersible pump is lowered into the borehole, connected to a rising main pipe that delivers the water to the surface. The wellhead is sealed with a cap and often a concrete slab to prevent surface water runoff and contaminants from entering the well.
Primary Uses and Applications
Bore water provides a valuable, independent water resource for various purposes. The most frequent application is irrigation, used to water gardens, lawns, and support large-scale agriculture and livestock. Using bore water for these purposes reduces demand on public water supplies and lowers utility costs.
In domestic settings, bore water is commonly used for non-potable tasks like flushing toilets, washing vehicles, and cleaning outdoor surfaces. Industrial and commercial users, such as construction sites or mining operations, utilize it for processes like dust suppression or cooling systems. The intended application is governed by its tested quality; water unsuitable for drinking may still be acceptable for irrigation or other non-consumption uses.
Ensuring Safety: Water Quality and Testing
Bore water is not automatically safe to drink and should never be consumed without professional testing. Unlike municipal sources, bore water is untreated and may contain contaminants that pose a health risk. The two main categories of risk are chemical and biological contamination, both requiring specific assessment.
Chemical contamination occurs naturally as water dissolves minerals while moving through geological formations. This can lead to high levels of metals like iron and manganese, which cause staining and affect taste, or harmful substances like arsenic and other heavy metals. Nitrate contamination is a common concern, often resulting from agricultural runoff containing fertilizers, and can be dangerous to infants.
Biological contamination includes pathogens such as E. coli bacteria, viruses, and protozoa, which can cause severe gastrointestinal illness. This contamination usually results from surface water infiltration, such as from septic systems or animal waste near the borehole. Regular testing by an accredited laboratory is the only reliable way to confirm the water’s quality and determine if treatment is necessary.
If testing reveals contaminants, various treatment methods can be employed to make the water potable. For biological risks, methods like ultraviolet (UV) sterilization or chlorination are effective at destroying harmful microorganisms. Chemical issues often require specialized treatments, such as reverse osmosis systems to remove high levels of salts and heavy metals, or oxidation filters to manage iron and manganese. A comprehensive water analysis must guide the selection of any treatment system.