How to Test Water From a Drinking Fountain

Drinking water quality is an issue that plagues public institutions, homes and the workplace alike. Water fountains can breed monumental amounts of bacteria, making toilet water look appealing in comparison. Water from water fountains can also contain various contaminants such as arsenic, mercury and lead. Routinely testing drinking water from water fountains is vital for protecting public health. This is especially important in public schools, where water bottles are banned and students are forced to drink from the water fountains in order to stay hydrated.

Things You'll Need

• Petri dish
• Small plastic screw-top sample bottles
• Incubator
• Q-tips
• Disposable rubber gloves
• Small plastic Q-tip containers
• Laminar flow hood or clean box
• p-10 micropipet
• 10 ml, 100 ml and liter graduated cylinders
• Microscope

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Instructions

Testing Water Fountains for Bacteria

• 1

  Find locations such as public schools or colleges which contain public drinking water fountains. Go to these locations and map the locations of all water fountains.

• 2

  Ask permission to test the water fountains for contaminants for proceeding any further. Once permission is granted, apply a small piece of tape to each water fountain, labeling each accordingly. Ex: Water fountain 1, Water fountain 2, etc.

• 3

  Insert a Q-tip into the spout of the drinking water fountain and rub in a circular motion to obtain as much sample as possible. Place the Q-tip into a Q-tip sample holder and label accordingly. Fill up a bottle of water from the same water fountain to replicate the amount of bacteria a drinker would normally be exposed to during water fountain usage.

• 4

  After samples have been collected, they need to be placed on an agar Petri dish for growth. Using a marker, divide a Petri dish in half. One side will be reserved for the Q-tip, while the other side will be used for the water sample.

• 5

  The water sample will need to be further diluted, since all drinking water contains some bacteria. Using a p-10 pipet, transfer 10 ul of drinking water sample into three separate containers, meaning 10 uL for each container. Using graduated cylinders, fill the first sample container to 10mL, the second to 100mL and the third to one liter. The purpose of this dilution is to separate the bacteria enough in order to visualize the amount of colonies originally in the fountain water.

• 6

  Divide the water sample section of the agar plate into three separate sections. Label them according to ml dilution (10ml, 100ml and 1000ml). Using the p-10 micropipet, transfer 10 ul of sample from each dilution container to the labeled sections on the agar Petri dish, starting at the highest dilution (1000 ml). Starting at the highest dilution is necessary to avoid contaminating the sample's concentrations.

• 7

  Apply the swab to the other half of the Petri dish. Make sure each Petri dish correlates to a certain water fountain, so experimental results are not misreported.

• 8

  Place the plates in an incubator at 37 degrees Celsius and remove after 12 hours. Place a plate under a microscope and view the diluted water samples. Small globules called bacterial colonies should be visible. Count the colonies for each sample. This method should allow for adequate comparison of bacterial contamination in a water fountain.

• 9

  After this step, the plates can be put back in the incubator for further growth. Once a significant amount of bacteria has grown from the Q-tip samples, it can be photographed and compared to the water dilution data.

Testing the Water for Non-biological Contaminants

• 10

  Find a laboratory online which processes water samples close to your location.

• 11

  Place the labeled water samples in a shipping container and ship them to the testing laboratory.

• 12

  Once the results have been obtained, compare them to average local water contaminants which can be obtained from your local water company.

• 13

  If the concentrations of contaminant are higher than recorded local levels, this could indicate a problem that needs to be fixed. An example is old lead pipes leaching lead into drinking water.

• 14

  Narrow down the water fountains which samples indicate the highest level of non-biological contamination.