What can be done if a water system is already contaminated or is suspected of being contaminated?

Bottled water: First off, you will need to stop using the water from that system. Get some bottled water. Secondly, the system will need to be inspected and once it's been done and the contamination treated, you may be given permission to start using it again.

Testing: The water supply needs tested to see if a filtration or other treatment method can improve the safety / quality of the water. Meanwhile, rely on bottled water for drinking / washing hands/hair/face.