Monolithic Signal

Last night we were disturbed by a high pitch signal which turned out to be emanating from our newly installed sewerage system.  I always assumed that sewerage systems consisted a basic structure of pipes and poo, and the concept that there was something high tech lurking below had never really occurred.  The high pitched squeal went on long enough to disturb the neighbours until the water company told us how to switch it off at the electricity mains.

A later disturbing development was when water company personnel turned up at 10.30pm.  They told us that signals had been set off in a number of systems in the area simultaneously and they had NO IDEA WHY!

Could our poo pipes be trying to contact aliens?