Low pressure kitchen faucet

[Delph]

Hello,
We have low water pressure in our pull down faucet only. Everywhere else in the house is normal. We have checked every part of the faucet, hose et water lines, et nothing changes. So we ended buying a brand new faucet, and installed it.... but the problem is the same!! So it doesn't have anything to do with the faucet itself. When we turn it on, the pressure seems normal for the very first micro second, and quickly weakens.
There doesn't seem to be a leak anywhere.
What could be the cause of this low pressure?
The hot water is not currently connected, we only use cold water. But this has been the case for about 4-5 months, and the pressure problem only started recently
.Any idea?

Thank you

 

[Twowaxhack]

Is there any change in flow when using all hot or all cold ?

Have you taken apart the stop valves or used a short section of pipe to connect to the outlet of the stop valves hot/cold and direct the flow into a bucket ?

This would tell you if it’s the faucets or your water supply to the faucet.

 

[Delph]

The hot water is shut off, so we can’t compare
We haven’t tried anything with the shut off valve yet, but that sounds like it should be our next step.
it does look corroded

 

[House Doc]

I just had this kind of a problem with a toilet supply the other day.
Is the pressure low on both hot and cold? There was a bit of broken washer inside the riser hose itself. Otherwise There is a flow restrictor someplace in the faucet.
Check the "specs" for the faucet and see if it actually delivers the amount of water it says it should.

 

[Twowaxhack]

Looks like you might have one of those fail safe supply hoses that limit flow if it thinks the line broke......

they malfunction and cut your flow down.

If that’s what you have, remove and replace it with a regular supply hose.,

the valve you have pictured doesn’t have a washer.....

 

[Delph]

It was indeed the shut off valve! We replaced it and the pressure is back to normal! Thank you!