I have a townhouse and there is sounds of running water coming from both the upstairs and downstairs bathrooms. I have a leaky tub faucet upstairs and there seems to be dripping noises coming from inside the toilet. Its been going on for awhile and there is no evidence of any leaks or water damage in my home. Is the sound from the upstairs tub making its way to the basement. Is it the toilet? Or perhaps our old water heater?

It can be seeping toilet, drip in tub, dripping garden hose valve etc. The noise will transfer throughout the house. The noise magnifies at night.

Any leak in your house is audible in your pressure regulator. Put your ear on top of the regulator and you will hear the noise.

You have to apply elimination method to find out what generates the noise. First, try to close angle stops at your toilet over night. See if the noise stops. If not, it may be the tub faucet. Replace the washers / cartridge in the faucet and see if it continues. Go from fixture to fixture...

But in any case, dripping faucet may and will produce noise in your plumbing system.