If you poison a ration of water, will you be able to put it into the well

One of the main construction sites you have to consider making in the game is the Pump. The Pump not only provides you with some opportunities to further improve your town's defenses with the strongest traps in the game, but also allows your town to obtain more water through upgrades. Through this mechanism, you'll be able to survive beyond four days even if nobody dies, and with good teamwork you should be able to avoid having to kill each other off to avoid dehydration.

Furthermore, it's possible to find Jerry Cans on the map, which, when purified using a Water Purifier Tablet, provide 2-10 extra rations of water that are immediately added to the town well.

I wouldn't stave off taking your water ration each day unless you're completely unsure with what you're doing with your AP; if your town's organized, you will get that Pump up.

The description is misleading. This item only works outside of town. You can't use it to hide actions you take in town like raiding the bank or upgrading your hovel to a castle.

When you use it, it will conceal anything you do in the zone you are standing in.