When ever I try and flush a toilet, and turn on a faucet at the same time I get very little water pressure and also get a hammering sound. I have a water pressure regulator at the water inlet. Could it be bad?

What type of material are your pipes made of? How old? If you have PRV valve you must have a gage nearby. What's your house pressure read? (I must kinow this) Regards, Tom

25 year old galvanized. No gages at present. When the house was first built there was 100PSI at the meter and the regulator was set for 45PSI as I remember.