I just purchased a home built in the 1950's. I'm having issues with water flow, if using the shower and the sink is turned on or the toilet flushed, I lose almost all pressure. The pipes are copper, but I've noticed that it appears to be 1 main supply to that bathroom. I think that is part of the issue, but am not sure. I was going to add a supply line for each fixture: toilet, sink, shower from the main lines. Is it a safe bet that this would fix my problem?

Probably not. If your lines are copper we presume there is little to no corrosion inside of them restricting flow.

The pressure to the house is constant... same as for all of your neighbors.

It's not uncommon that water pressure to one area is reduced if water to other areas is being used.

So to make a long story short, it sounds like the issue just goes with the territory.

... but it couldn't hurt to call a couple local plumbing companies for a free estimate - to see if they can identify something wrong... BUT if they DO say something is wrong, don't pay them until and unless you have confirmed that the problem is solved. Look at the contract carefully.

What size it the pipe between the main and the bathroom?

I just purchased a home built in the 1950's. I'm having issues with water flow, if using the shower and the sink is turned on or the toilet flushed, I lose almost all pressure. The pipes are copper, but I've noticed that it appears to be 1 main supply to that bathroom. I think that is part of the issue, but am not sure. I was going to add a supply line for each fixture: toilet, sink, shower from the main lines. Is it a safe bet that this would fix my problem?

Hi Mike and Welcome to The Plumbing Page. At AskMeHelpDesk.com. I live in a 50's house. You have a volume problem that causes you to lose pressure. Our homes were originally piped in galvanized iron pipes. Over the years the pipes build up rust and cut down on both volume and pressure. That's the time most of us got a repipe job in copper. All well and good. But if the water service line's still galvanized then you have found the source of your problem and all the branches you run into your bathroom from the main will be useless . Go outside and tell m me what type of pipe you have on your water service. Try this. You should have a hose bib near where the water enters your house. Turn it on and have someone inside run the bath tub and flush an toilet. If the pressure falls to a trickle then you've located the source of your pressure loss. Let me know what you find. Good luck, Tom