Were I in Ceci's situation I would be suspicious that the saboteur were intent on more harm than just polluting the water. Therefore I would seek to not act in a predictable way as a result of the water sabotage.

It is very predictable that a trip to acquire water would follow soon after such sabotage, so I would only undertake such a trip if no other options were available, and only with extreme caution.

Were I in that situation I would seek to make a water filter. The most important component is charcoal, which is just wood that is prevented from burning up completely.

My best to Ceci.