Any time that you are uncertain of the purity of your water, treat it before you drink it. If the water you are planning to use looks cloudy, the first step should be to pour it through a coffee filter or a piece of cloth to remove any solids. Never try to treat water that smells of petroleum.
Filtration is one method of obtaining safe water.
A standard filter on a kitchen faucet is practical, but is made to clean pretreated water and might not remove bacteria and viruses. In an emergency, you may wish to use a portable water filter designed for camping. This is basically a hand pump connected to two tubes and a filter. Keep in mind that all water filters are not equally effective. The EPA has established guidelines for water purifiers.