Bizarre Electric Shock

I read some bizarre incidents daily in the newspaper but I haven't witnessed one until this happened at home. We bought a plastic drum a few months ago to store water. My husband himself fixed the tap on it. After filling the drum with water when checking for the water flow from the tap he felt an electric shock and came out from the bathroom and told me. I couldn't believe at first. I thought he had gone mad. But he doesn't believe in such things. so he got confused on it. When tested with a tester it showed spark as if it is from an electric socket. My husband's hand showed more powerful spark than mine. Usually I am subjected to such problems. When I touch the switch board or electric appliances I feel a vibration through my hands. I hesitate to use the drum. What a way to produce electricity! I didn't tell anybody about it till date fearing a crowd will rush into our home to catch a glimpse of the bizarre.