Agatha Raisin and the Wellspring of Death by M.C. Beaton

Agatha Raisin and the Wellspring of Death (Agatha Raisin Mysteries, No. 7) - A water company wants to bottle and sell the water from a spring in a nearby village.  Agatha finds one of the parish council directors dead in the spring.  Roy Silver talks Agatha into being the public relations representative for the water company.