Every community has a method for pre-treating drinking water from a ground or surface water source. Sometimes the term water purification is used for this treatment, but this term incorrectly suggests that the end result of this process will be pure water, with no impurities. A better term to describe this process is water treatment. In order to be assured that water from a well, stream, or lake has enough impurities removed by water treatment to be used as drinking water, it must go through several water treatment steps. These steps may include settling, filtration, or chlorination. Far from making the water “pure,” the treatment will in many cases simply reduce some impurities to a level found to be acceptable by government agencies. Some typical EPA (Environmental Protection Agency) standards for drinking water are shown in this table.

In this experiment, you will treat an untreated water sample supplied by your teacher. You will use a number of different methods, including settling, filtration and pH adjustment, to treat your water sample. Before and after the treatment, you will monitor three different indicators of water quality—pH, total dissolved solids (TDS), and turbidity—to see if each quality improves.


In this experiment, you will

  • Use a pH sensor to measure the pH of the pre-treatment and post-treatment samples.
  • Use a conductivity probe to measure the total dissolved solids (TDS) of the pre-treatment and post-treatment samples.
  • Use a turbidity sensor to measure the turbidity of the pre-treatment and post-treatment samples.
  • Use the test results to see how much the treatment improved the quality of the drinking water sample.
  • Compare the drinking water sample to EPA standards shown in the introduction.