Townhouse water pressure question...


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Old 01-12-22, 11:25 PM
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Townhouse water pressure question...

We live in a townhouse. There are probably 100 other units here. Each one has a water shut off valve near the garage door. The water pressure seems very high, and we've mentioned it before but got no reply.

The units are about 30 years old, and some of the pipes at various units have been leaking lately. My neighbor told me (a retired Scottish plumberócool guy...RIP) that the original contractors used low-grade solder when they built the units to save money.

So, I decided to turn the water knob down (that's in front of my unit), to lower the pressure. Thinking that may go easier on the plumbing.

However, the plumbers that the HOA use for a lot of projects, told me the water pressure is the same if I turn that knob down or up. That the water pressure is only controllable at the main line in the front.

Is that true?
Because if I turn the knob at my garage all the way up, all my appliances have an insane amount of water pressure. If I turn it down a bit, it seems more normal.
 

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01-13-22, 04:52 AM
Pilot Dane
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Partially closing the main shutoff to your condo will lower the water pressure in the condo ONLY when you are using water. The faster you use water the lower the pressure will get since only so much water can flow through the partially closed valve. But... when you stop using water, within seconds, the pressure inside the condo will rise to be the same if the valve were left wide open.

If you want to reduce the water pressure in your unit the only solution is to install a pressure reducing valve (PRV). They cost about $75 and are not difficult to install if you are comfortable with plumbing. The valve should be installed on the water main to your condo. Most are adjustable so you can set the pressure you want.
 
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Old 01-12-22, 11:42 PM
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You are confusing water pressure with flow rate. The pressure is the same, you are just limiting the gallons per minute which "seems" to result in less pressure. Less flow, same pressure. Just like putting your finger over the end of a hose. You aren't changing the pressure by limiting the flow.. it's just forcing a certain volume of water (determined by the pressure and the pipe diameter) through a smaller orifice.

You aren't harming anything by limiting the flow rate but its not really the ultimate solution.
 
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Old 01-13-22, 04:42 AM
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Its called the Bernoulli's principal, fluid dynamics, from the old days in physics.

The speed of water through an orifice, the valve, increases or decreases with a respective change in pressure, but it's at the valve only the pressure upstream and downstream is essentially constant!

When you say state high pressure, leaks, and cheap solder, they are not really related. Plumbing fixtures and pipes can withstand hundreds of lbs of pressure and a soldered joint is not effected by pressure.

Depending on how the complex is plumbed it could be a simple solution of installing a PRV pressure Reduction Valve on the main.
 
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Old 01-13-22, 04:52 AM
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Partially closing the main shutoff to your condo will lower the water pressure in the condo ONLY when you are using water. The faster you use water the lower the pressure will get since only so much water can flow through the partially closed valve. But... when you stop using water, within seconds, the pressure inside the condo will rise to be the same if the valve were left wide open.

If you want to reduce the water pressure in your unit the only solution is to install a pressure reducing valve (PRV). They cost about $75 and are not difficult to install if you are comfortable with plumbing. The valve should be installed on the water main to your condo. Most are adjustable so you can set the pressure you want.
 
CasualJoe, Zorfdt voted this post useful.
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Old 01-13-22, 09:55 AM
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L-

You can check further but if the shut-off you are using is a gate valve, I believe you are really not supposed to use those for throttling the flow. I’m pretty sure that harms a gate valve. I think they are meant to be fully opened or fully closed.

I am thinking they probably used a gate valve to shut off an individual unit. Could be wrong.
 
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Old 01-13-22, 10:58 AM
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Pick up a test gauge at one of the home improvement stores to verify the water pressure.

Water pressure test gauge
 
 

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