I have a single family house on city water pressure that has an issue when multiple things are using water. For example if the washer is running then the shower will only have a little trickle coming out. If showering and someone flushes a toilet then only about half as much water comes out of the shower. It's lead to some funny times when someone is in the shower and another person puts a load of laundry in only to hear yelling come from the person upstairs. As funny as it can be sometimes it is a nuisance and I want to remedy the situation. I thought at first that this was only a pressure issue but used a pressure gauge at the first connection I could find on the main line coming into the house and it is OK.

After taking a closer look at where the water comes into the house there seems to have been an old repair at a 90 before the first valve inside the house. Right after the 90 the copper pipe necks down from 3/4" to 1/2" and then again to either 3/8" or 1/4" from what I can tell. It is only a short little section but I think that may be causing my issue. I know I'll need to call the city to shut the water off to my house while I replace the section of necked down pipe but before I go through all of that I'm wondering if I'm on a wild goose chase or actually may have found what has caused my issue. Can a small section of necked down copper piping as it comes into the house cause what I've described above?

 

Most definitely, YES!

RR

 

3/8"?? In the main supply?! Heck yeah that's the problem. Well, at least a major problem. Might not be the only one.

Btw...if you have access to the shutoff, you may not need to call the city. You can buy what's called a "curb key" to reach down and shut it off if it's in the ground at your home. Normally, home centers ad hardware stores will sell the type most common in your area...they can be 2' or 6' down. Out here they are at about 6"...lol. That's assuming you have individual shutoffs. Where is your meter located?

 

All main runs should have been 3/4", then stepped down to 1/2" for the supply's
Only place 3/8 would be used is for the final supply's for the sinks, dishwasher and toilet.
A 1/2" line has 1/2 the flow of a 3/4" line.

 

The only other thing that would cause that drastic a pressure reduction would be a faulty PRV. Do you have a brass device near where the water line enters the house?

 

Thanks for the feedback, the photo shows where the pipe narrows right after the elbow after it comes into the house through the basement wall. There are a couple of buffalo boxes out by the curb which is where I assume there is another valve and meter (there isn't one inside the house) but I haven't opened them up to see what is inside yet. I'll have to take a look to see what is in there and whether there is an extra valve or only the city one. I've heard its illegal to turn the city valve and that it costs $40 to turn off and another $40 to turn on....

 

You might want to verify with the water dept if it's illegal to turn off your own meter. Generally it's only illegal to turn on a meter that the water dept has turned off.

I also have poor water pressure but that's because I'm on top of hill, I've not had over 20 psi in the last week - makes taking a shower difficult. Except for an ice maker - 1/4 piping has no business being in a house.

 

Here you can legally turn off and on the water supply all day and all night with no problems. However if you cut the lock-out band after the city turns off your water and bands the valve closed, you'll be a heap big trouble with the law.

 

Hard to tell what's coming in from the street. Looks like possibly steel.
Can you tell if it's copper ?

 

In your particular jurisdiction it MAY be unlawful for you to use the water utility's valve. I personally have never heard or read about someone being prosecuted for this. HOWEVER, there IS one thing to be aware of, some of these valves have not been used in decades and may be extremely hard to turn. If YOU break it the entire cost of repairs will be on your shoulders. If the utility worker breaks it the utility is liable for the repair costs. These costs could be considerable.

I think I would locate the valve. obtain the special wrench (if one is required) and test it first. If if moves easily then you are probably good to go. If it does not move easily I would spend the money to have the utility close and open it.

 

It's also possible that an old meter won't shut off completely. That is the problem with mine, I had to install a ball valve on my side of the meter in order to stop all water flow.