Is clear water pumped from a deep aquifer a pure substance?

Yes

Explanation:

As pure substances are substances that are formed directly by elements and water is directly formed by the union of two elements which is Oxygen and hydrogen, H2O is the formula and that is a pure substance as it is conformed mainly by only these two elements, so the question would be Yes, clear water pumped from a deep aquifer is a pure substance.

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume

the dependant variable is spilled water

the independent is the heat