House water pressure gets super low when toilet is flushed.

[Sdsad123]

So, recently, over the last 2 weeks or so I've noticed that when a toilet is flushed the house water pressure gets very low.

• When I'm taking a shower, it seems to affect it no matter what. The hot water and cold water are equally affected. Occasionally the bathtub/shower will make a squealing noise that I can occasionally stop by jiggling the nub thing.
• Even if no toilets are flushed the shower will usually start off with regular water pressure and then get lower (but not as low as when I flush the toilet).
• Often all the faucets in the house will be equally affected (hot and cold).
• Once or twice I've noticed that the hot water will be affected but not the cold (kitchen faucet).
• Sometimes when I flush a toilet nothing happens (everything is fine).

I'm honestly unsure of what to do at this point. If I have to hire a plumber I wouldn't mind, but if I can figure this out by myself (with your help) that would be great. Thank you!

 

[Terry]

What year was the home built?
What kind of pipes do you have,
Galvanized
Copper
CPVC
PEX

 

[Sponsor]

 

[Sdsad123]

What year was the home built?
What kind of pipes do you have,
Galvanized
Copper
CPVC
PEX

Home was built in 1985-1987.
Pipes are copper with some PEX.
Installed a softener probably 4-5 years ago that still appears to be working fine but no other filters or anything.
Municipal water.

 

[Jadnashua]

In the shower, do you notice any rusty water? In that timeframe, copper got quite expensive, and instead of using brass or copper fittings for the shower, they may have used galvanized. That stuff, over time, will rust. That can make the ID quite narrow. Pressure won't change, but volume will. For a shower head to feel good, it needs enough volume to have a restriction right at the nozzles for the head to cause the water to speed up.

 

[Sdsad123]

In the shower, do you notice any rusty water? In that timeframe, copper got quite expensive, and instead of using brass or copper fittings for the shower, they may have used galvanized. That stuff, over time, will rust. That can make the ID quite narrow. Pressure won't change, but volume will. For a shower head to feel good, it needs enough volume to have a restriction right at the nozzles for the head to cause the water to speed up.

It had been a really long time since I’ve noticed rusty water from the faucet in the shower/tub. Like a year or so I’d say. It did used to do it but I think once we started using that shower more it stopped doing it. Also would that one shower cause issues for all of the house? Because sometimes it’s a whole house thing. I think when the shower is on and the toilet is flushed the whole house CAN get low water pressure but sometimes it varies. Very weird. Thanks for helping!

 

[Jadnashua]

FWIW, if you use the shower regularly, you may not notice much rust, but it's still happening. There should not be anything that can rust in that path.

All it takes is one fitting somewhere that is getting rusted out, creating a restriction. So, gather up a magnet, and look at the pipes from when they come into the house as far as you can follow them and look for anything made of iron...it could be more than one thing, and, yes, it could be closer to the point where it comes into the house and there could be more than one fitting that's causing the problems.

If you have a pressure reduction valve, one of their failure modes is funky pressure, so that could be a problem, too.

While funky pressure can cause that, what you're describing is more likely a volume issue caused by a restriction. A galvanized fitting or nipple somewhere can narrow down to about a soda straw before enough rusts away for it to start leaking. That will cause significant volume reductions, so when you ask for more, you notice it dropping off volume everywhere.

 

[Terry]

A fairly recent home it sounds like. Copper and PEX shouldn't be an issue. I too would check to see if you have a PRV pressure reducing valve there somewhere. Sometimes the screen in those gets dirty and prevents a good flow.

 

[Sdsad123]

A fairly recent home it sounds like. Copper and PEX shouldn't be an issue. I too would check to see if you have a PRV pressure reducing valve there somewhere. Sometimes the screen in those gets dirty and prevents a good flow.

Would this be outside of my house or inside? I have to admit from a quick googling that we dont have one.

 

[WorthFlorida]

For Illinois, a PRV would be in the basement.

 

[Jadnashua]

I'll say it again...if you were seeing rust, there must be some iron fittings somewhere in the system...as they rust, the rust gets larger in volume and can create a significant obstruction, lowering the available volume. Volume and pressure are related, but not the same thing. WIth a significant restriction somewhere, once you try to demand more than what's available, there will be a reduction everywhere. Think of a soaker hose...it has the same input as a regular garden hose, but has many more outlets, so the volume on any individual outlet goes down.