If you choose to create a sand filter you have the option of making a slow or fast filtration system both of which are effective.
Rock and sand water filter.
Some of the impurities are microscopic but many are large enough to remove with a crude filtration system that you can make yourself using sand and rocks.
As water flows slowly through the sand these organisms form a biofilm that traps and consumes other micro organisms including those that make people sick.
In recent history the past 150 to 200 years it.
The water filter diy with sand is quite different from the simple filtration system as it requires more components and is a more complex but better way to clean your water.
In a biological sand water filter micro organisms most of them harmless grow and cling to the surface of sand particles inside the filter.
Then after constructing the filter he continued to filter some dirty water and commented that the first little bit is going to be nasty since its getting the dirt off the sand and rocks in the filter.
He commented that since the charcoal is very porous it s great for filtering.
Saw a video on youtube where some guy made a water filter out of a bottle charcoal sand and little rocks.
Very little of the water we use every day comes out of the ground completely pure.