pipes groan on regular interval and then toilets rattle

[achtungpv]

Just moved in to a new (built in '65) house. On a regular basis, maybe every 10 minutes, the pipes make a low groaning noise and then the toilets hiss and rattle. When I look in the toilet tank while the toilets are rattling, there are bubbles coming up from the gasket where the water line connects to the tank and the float structure shakes.

No other water fixtures are turned on when this happens.

Any ideas?

 

[IFIXH20]

Sounds like your toilet tank is loosing water and the fill valve is refilling the tank. Your flapper might be the problem with loosing water out the tank. The groaning noise could be caused by a worn/bad fill valve