How did they know where to dig water wells in the past?


How did people know where to dig a well before they had access to technology we have today (or the possibility to use drills we have now that you can use pretty much everywhere and drill deep enough that you’ll find water anyway)?

If you’re only using manual labour, you cannot dig very deep so finding water isn’t guaranteed. So how did they figure out where they should dig to find water? (I mean especially in the context of wells on farms or communal wells in villages.)

In: 4698

They look at the hills around them. If humans haven’t moved them all around with bulldozers, the surface is strongly related to the structure underneith. Water isn’t hard to find, unless you’re in the desert, where the structure is even less eroded.

The best place is near a river. Of course a river is not always close to where you can build a house. Its rough if there are no wells anywhere around your property, but all the nearby wells will be at the same depth. Its called a “water table” because its at a very flat level. If your neighbor hit water 20 feet down, then you will probably hit water 20 feet down.

If you look at places where a hill was cut away to make a highway, you can see the different layers. When it rains (or a river is nearby), water percolates down through the soil until it hits a layer of sand, and just below the sand is clay. This is pretty common across the USA. The water goes down until it hits the clay, and then it flows sideways in all directions.

In some places its deep, and in others its close to the surface. The location of easily accessible water is the key to building a settlement. Not only do you want water on your property, you want your property to be near the properties of other people who are like you and also can reach water.

Then, you dig a well until you reach water. Of course you need to shore up the walls so it doesn’t collapse in on you, which is why it’s usually cylindrical and lined with fitted stones.


There’s actually a layer underneath the soil where there’s a bunch of water-saturated dirt. It’s called an “aquifer”. If you get to it, you get water to “well” in the space. Unless you’re in a desert, water is a constant.

The thickness (and depth) of the water table can vary based on the terrain & rainfall. This means you can generally make an educated guess from the environment.

In a given area tho, the table is often pretty flat. If a nearby town has a well that worked at X depth, you’ll typically be fine around that deep too.

That said, “water witching” was the original explaination. Basically, “Bippity Boppity Bullshit, Water Is Right Here Because The Spirits Say So”. One of the oldest cons in the book, but people believed it because they were basically betting on rounding errors.

Honestly it is pretty simple if you look around you. Ever notice that a lot of low lying areas are damp? That puddles form in places that take a while to go away? This can happen for a few reasons but mainly it means water is fairly near the surface. It’s not a guarantee but they dig. Sometimes they might just hit a massively impermeable layer and that’s why water sticks around but they figure it out quickly.

They don’t usually build homes and then worry about water. Civilization followed water, usually rivers and other areas feeding into them. If they didn’t get good access to water quickly, there just wouldn’t be a well or homes there.