Water pressure Question ...older house

The house is 2 stories built in 1935. It has a finished basement with a 40 gallon water heater inside the basement. I see copper plumbing connected to
the water heater…I cant see if the total water supply plumbing has been upgraded to copper.

All the inside faucets have average/serviceable water pressure. ( kitchen sink,and two baths ). The issue…is when one or more faucets are turned on
at the same time. Then one siphon’s or takes away from the other. ( At an
above average rate ).

What could be the problem? The water pressure coming to he house from the
street is 60psi.


There is a restriction some where a tap not fully turned on or galvanised pipe rusting inside or a kink in in a pipe some where .
It also could be an extremly long feed pipe to the home.
This is just a few things to look for .

Galvanized pipe restriction is the # 1 as the flow is increased there is more restriction of the water flow due to corrosion inside the pipe and this is generally in the hot water lines for various reasons.

Pressure and volume are not the same thing.

Increasing pressure will not always increase volume.

Restriction can be from a defect or it’s design.

Thanks everybody for feedback…

I have inspected a boat load of old 2 stories with galvanized iron water distribution piping from back in the 30’s and 40’s they are just like the arteries in old mens legs close up from the inside.:frowning:

I have a simple test I perform open two faucets somewhere in the home it matters not where. Then go to a shower and if there is not sufficient water to get a decient shower I call for the replacement the distribution piping. It has never failed me yet

Galvanized pipe is probably present in the walls,or the main supply line is too small to find this quite often around here.

Thank you Charley…

As Wayne mentioned… portions of the original, galvanized plumbing may remain or there are other restrictions present. If reduced flow is noted when 2 or more fixtures are operated at same time, write it up!

I had an interesting experience with my own water heater over the last couple of months. The hot water flow diminished to the point of almost no flow. I thought the water heater was the problem as the cold water flow was very good.
I decided to flush the Water Heater and disconnected the hot water outlet so I could drain and flush the tank. When I took off the isolation fitting I found it almost completely plugged with calcium deposits. I was amazed that a 1/2" of galvanized iron between the copper and water tank could clog up the whole hot water supply.
I cleaned the fitting and it should be good for another 10 years.
So the next time you find poor hot water flow, good cold water flow, the distribution pipe is copper and galvanized iron isolation fittings on the water heater, flag it as the first thing to check.