How does a well work? Is there a finite amount of water in a drinking well? Why is it okay to drink? Do they somehow replenish water or if they dry up that is it?


How does a well work? Is there a finite amount of water in a drinking well? Why is it okay to drink? Do they somehow replenish water or if they dry up that is it?

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Ground water can be at quite a low level in a lot of places.
Just dig a hole a few metres (a few more feet, i dont know…) down and your hole will start to fill with water soon enough.
Take out a few buckets and soon enough, the level will rise again to “ground water level”

Its ground water so usually not contaminated by much.
The ground is actually quite a decent filtration device.
Just make sure to keep animals from falling into your well (by covering it with a lid)
And of course its all within reason.
No well has water we’d consider extremely clean.
Its usually just “safe enough” but better to boil it first

During long periods of drought, the ground water level may fall and the well may run dry.
If the water level rises, so does the well refill.
But if your local farmers dig a canal to water their crops, the well may run dry more permanently.

Modern wells are generally drilled into bedrock. Rock is porous, even something like granite. So the water moves in underground streams called aquafers through the rock, which filters all of the bad stuff out of the water. Unfortunately, it can also put bad stuff into the water, like various minerals — even arsenic. That’s why people with wells should test their water periodically, to make sure it’s still OK.

The well itself is a hole drilled into the rock bearing the aquafer. It’s about 6-8 inches wide and usually somewhere between 200-800 feet deep. It fills with water, which is pumped out, and can seem ‘infinite’ as long as it’s not pumped out faster than it’s replenished.

However, aquafers aren’t infinite, and too many wells into a single one can deplete it, or slow the rate at which it refills the well.

Typically there is a water table, or a depth where if you were to dig you would hit water. They drill down below that depth and add a pipe to pump the water up.

When it rains the water goes into the ground and fills the well but during drought season it can go empty if more water is used than what the well holds.

(Literally just went through that with a sale of my fathers property. 75′ wasn’t deep enough for the buyer to run 300 gallons to test the septic…)

Wells work using the water underground. The ground is full of little cracks and lets water seep down into it when it rains. Some of this is lost on the surface due to evaporation but some of stays in the ground. Using scientific methods we can see how far below the ground the water is. This is known as the water table. If you dig a hole that goes deeper than the water table, the water, following gravity, will flow into the gap you have just dug. This fills it up the hole and is how wells replenish thier water.

The best example i can give of this is digging holes in the sand at the beach. The water table there is pretty much level with the sea. When you start digging the sand is dry, then it seems to get more ‘wet’ the deeper you go. And when you get below the water level the hole fills with water quickly.

Most wells get their water from aquifers. An aquifer is a layer of rock and soil with water flowing through it. Groundwater drips slowly through the small spaces within rocks, between rocks, and between loose materials such as sand and gravel. New water, such as from rain or melting snow, drips into the ground. The layer of ground just below the surface is a mix of rock, soil, water, and air bubbles. When gravity pulls the water in the ground deep enough, it fills all of the possible pores and cracks, forcing the air bubbles up. At this depth, the ground becomes saturated with water. The boundary between the unsaturated ground and the saturated ground is called the water table. The exact location of the water table depends on how much new water there is, how quickly the water is flowing away, and how permeable the ground is. If you dig a hole into the ground that ends below the water table, the water in the saturated ground is pulled by gravity into the empty space at the bottom of the hole. The hole fills up with water that drips out of the holes in the rocks. A well is simply a hole dug deep enough that it is below the water table, and therefore fills up with water. Old wells used buckets to remove the water from the well, and modern wells use pumps powered by electricity to drive water up. Because the water goes through layers of sand and rock, it is usually clean. But it depends on what kinds of things are in the sand and rock. That’s why well water has to be tested regularly.