Parasites are a byproduct of other types of contaminants, such as bacteria. If a water sample contains bacteria then parasites are most likely present. To check water for bacteria you need to use a testing kit to culture a sample. You can then examine the sample to see if any bacteria is present. If water has any type of contamination then it may not be not safe to drink without sterilization.
Turn on a water faucet in your kitchen or bathroom. Allow the water to run for a couple of minutes.
Fill the small bottle from the water testing kit with water.
Dip the tip of the pipette or syringe into the water and extract at least five milliliters of water.
Transfer the water sample to the vial.
Place the topper on the vial and then mix the water for at least two minutes.
Pour the contents of the vial on the petri dish. Set the lid in place and set aside for 45 to 60 minutes.
Wrap the petri dish in aluminum foil and set upside down on a window ledge or other sunlit area.
Remove the petri dish from the foil after 48 hours. Examine the petri dish to see if any contamination is present. Contamination consists of bacteria colonies that appear in the sample.