Get out of your house as quickly as possible and call the police. Someone has obviously planted a c4 charge in your water heater. To make it easier for the FBI compile a list of everyone who would have cause to harm you or your family in any way.
Completely normal. Chances are it only ticks when hot water is running, that is because it needs to work to keep heating the water.
The ticking could be just the pipes expanding and contracting. Or, the heating elements could have a build up that occurs over time.
there is a bit of rubish caught in the heater fan.
The cool water hitting your piping hot exhaust makes the metal contract (Shrink) and it makes a ticking noise.
most likely a faulty relay
If it makes the ticking sound and the engine will not crank, then either your battery is dead or the starter solenoid is shot.
A sound at 15 decibels is not very load. It is equivalent to the sound that watch makes when ticking.
Not enough power to starter motor.
The most likely cause of a ticking sound in a motor is a bad timing belt. A valve out of time can also cause a ticking sound.
the ticking is the blinkers
Get your brakes tested. I do not know what a ticking sound means.
that probably means its time to get a new car