If any faucet is on anywhere in the house and you run anything else the one already on immediately goes red hot. When I flush the toilet for instance and my wife has the kitchen sink running, it will immediately go scalding hot given it is at a warm water setting. If the setting is cold, then the pressure will drop. If I'm in the shower and the washer runs it goes hot in a hurry. What can be done to regulate the pressure?

What kind of water pipes do you have? My bet's on older galovanized pipers. Am I correct? Tom

What kind of water pipes do you have? My bet's on older galovanized pipers. Am I correct? Tom

Um, unsure, house was built in 1973

Could be either copper or galvanized. Find some bare pipes, like water stubouts coming out of the wall or the water heater hookup and let me know.
Cheers. Tom

All copper

If any faucet is on anywhere in the house and you run anything else the one already on immediately goes red hot. When I flush the toilet for instance and my wife has the kitchen sink running, it will immediately go scalding hot given it is at a warm water setting. If the setting is cold, then the pressure will drop. If I'm in the shower and the washer runs it goes hot in a hurry. What can be done to regulate the pressure?
Most people think this would be a pressutre problem. While the result is a loos of pressure it's really a volume problem. Here's how it works out. While you can have volume without pressure you MUST have volume to have pressure. A typical complaint goes like this. Minerals build up in the pipe walls over the years cutting down the amount of water,(volume) that can pass through the pipe. Your honey's going rub-a-dub in the shower and you're on the throne in the second bath. Now she has the hot and cold set just right for her. You flush! Big mistake! You have diverted the cold water flow from her shower to your toilet tank. As a rule this wouldn't matter since there would be enough volume to service both draws but with the reduced capacity in the cold water line the volume to the shower is cut in half and the cold water pressure drops. But the hot water volume and pressure remain the same allowing more hot water to come in and the temperature in the shower hits "turn and burn" for the little woman. (Now here I speak from experience) SHE'S Going to THINK YA DID THAT ON PURPOSE!
Now for a short term fix you could install a in-line booster pump after the water comes into your home but the real repair for that situation is a repipe job. Sorry it took me so long to come to that but I wanted you to understand what was happening and why. Good luck, Tom

Repipe job... dang... whats involved with installing an in line booster?

To check on in-line booster pumps click on ;Davey’s HS multistage booster system with Hydrascan control gives strong, even water pressure HS12-30HT1,HS12-40HT1,HS18-30HT1, HS18-40HT2, HS20-65-Ht2, XF14-30K1 (http://store.waterpumpsupply.com/davpumboossy1.html). Let me know what you decide. Good luck, Tom