Another George A. Romero film, which isn't the best, but still good.
In a small town of Pennsylvania, a government plan crashes carrying biological weapons. This deadly weapon seeps into the water supply and anyone who drinks it becomes crazy and murderous. David (Will McMillan), a firefighter and his wife, Judy (Lane Carroll) and a few others attempt to escape the town.
Romero is able to take away the living dead and replace it with ordinary people and it works very well. He is able to keep the nightmare going throughout the entire film.
They did remake this movie and I didn't get a chance to see it yet, but I heard nothing but great things about it.