Porakaivo

Porakaivo is a borehole or drilled well used to access groundwater. In Finnish contexts, porakaivot are a common source of private water supply in rural areas, drilled to reach underground aquifers in soil or bedrock. A porakaivo differs from a dug well in that it is created by drilling rather than excavation, and it typically uses a casing and a screen to isolate the water-bearing interval and to prevent collapse or contamination.

Construction and components: The borehole is drilled with appropriate methods, such as rotary drilling or percussion, depending on geology. A casing (usually plastic or steel) is installed to prevent the sides from caving and to seal out surface water. A screen may be placed at the intake zone, with gravel packing and grout to consolidate the surrounding formation. A surface seal, a concrete cap, and a protective well head are installed. Water is pumped to the surface by a submersible or jet pump, and conveyed to a building through piping and, often, a pressure tank.

Water quality and treatment: Quality depends on the aquifer. Common concerns include hardness, iron, manganese, and microbiological contamination. Depending on results, treatment options such as filtration, water softening, UV disinfection, or chlorination may be used. Regular testing is advised to monitor quality and identify changes in yield or contamination.

Regulation and maintenance: Drilling is typically carried out by licensed well drillers and may require local permits and adherence to construction standards. The well head should be protected from surface runoff and infiltration. Routine maintenance includes inspecting the head, testing water quality, and servicing the pumping system.