loud hammer noise when neighbour turns off tap?

we live in the country side and have a "shared main" i.e. our house is at the end of a main shared by thee houses, my neighbour has receintly replaced her kitchen plumbing, since then, whenever she turns off her kitchen tap a shock wave travles down the pipe to the end of the line - our cold water storage tank, it sounds like some one hiting the tank with a sledge hammer!! any ideas? P.S. we dont get on to well with this neighbour so I guess its our problem.