Low Water Pressure

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  #1  
Old 08-15-13, 10:13 AM
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Low Water Pressure

I am a first-time homeowner and I'm trying to understand how water pressure works. In the past 9 months that I've owned my home, the water pressure has gone from fine, to not so good, to bad, to worse. The house was built in 1900 but numerous upgrades have been made throughout the house over time.

I hadn't really noticed too much of a problem until spring came around and I wanted to link 2 sprinklers up and water 2 areas of the lawn at once. There wasn't enough pressure in the line to power both sprinklers at once. To solve this problem, I ended up buying a timer and connecting it to the hose bib and had each sprinkler going off one after another.

I then noticed that I couldn't really run water anywhere else in the house if the sprinklers were running because if I turned on a faucet, flushed a toilet, etc. there would not be enough pressure to run the sprinkler.

Now it has gotten to the point where even with the sprinklers not running (but the timer still hooked up) if I flush the toilet and then try to start the shower, the pressure in both is a lot lower. I don't remember having this issue when I first moved into the house.

I have not tried shutting off the water at the exterior hose bib and seeing if that changes anything yet. It seems to me like I should be able to at the very least have enough pressure to link 2 sprinklers together.

Anyway, long story short... I have some questions now.

Where does water pressure come from? What controls it? I know that a bunch of things can inhibit it, but where do I start looking at how can I narrow down the issues? If I wanted to hire a professional to take a look at this for me, who do I call? Will the local plumber be able to do this? Do I need to call the city water department?
 
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Old 08-15-13, 11:00 AM
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Iím just a newbie but Iím sure the more knowledgeable folks will come to your aid. Sounds like you are on city water. There should be shut-off valve near where the water line enters your house. If that isnít open all the way you could have low pressure.

Also I believe many (maybe all) homes on city water have a pressure reducing valve (PRV)which ensures the water pressure in your home doesnít get too high. Those are bell-shaped and I believe there is an adjustment screw on them. I think those valves can sometimes go bad however. That valve should also be where the water line enters your house.

If you have any kind of water softeners or filters sometimes if they havenít been maintained for a while they can cause low pressure.

If the pressure problem is through the entire house seems like it would one of the above problems. If it is a bad PRV I donít imagine that would be too expensive (at least I donít think so).

Good luck, hope the folks in the know jump in!
 
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Old 08-15-13, 02:29 PM
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I found this video on youtube that explains the Pressure Reducing Valve and how to install one and adjust it. He uses a gauge you can buy which are pretty cheap, and he put it on a hose bib to check the pressure after installation. But it shows how the house pressure may be tested and adjusted with that valve. I think you would thus be able to figure out whether your PRV is good or bad. At least it seems that way to me.

I don't know whether the experts here think, hope they jump in.



p.s. The guy almost sounds like he is stoned - lol just kidding!

How To Install A Water Pressure Reducing Valve - YouTube
 
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Old 08-15-13, 02:34 PM
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Pipes

Most likely your pipes are clogged with rust.
 
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Old 08-15-13, 02:51 PM
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Wirepuller I was thinking about that, but since the water pressure went from fine to worse-than-bad in just 9 months - could it really be clogged pipes?

p.s. plus it's city water, shouldn't it be pretty good?
 
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Old 08-16-13, 04:05 AM
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I'm not a plumber, don't like plumbing but dislike paying a plumber even more

That said, I'd get a pressure gauge. You can get them at the big box for $10-$15. That way you'll know exactly what the pressure is without guessing. I'd then screw the gauge on to various hose bibs with both the water running and off. That should give you a better idea of what's going on and where to start. You could even install a hose bib before the PRV to verify what the pressure is before it reaches your house.

I live on top of a tall hill and deal with low water pressure on a daily basis. One big issue I have is whenever they work on the lines, trash seems to work it's way into my system and the low pressure isn't enough to blow it out.

It might also be helpful to know what type and size pipes you have throughout your system.
 
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Old 08-16-13, 04:51 AM
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To Wirepuller's point, unless someone has completely redone the plumbing, it is extremely likely that you have at least some if not all galvanized pipe, and once it starts plugging up, yes, it could have that much effect in that amount of time. I would start with a visual inspection, to determine the type(s) of plumbing that you have, how much of various types, and then probably take the path that Mark suggested, in order to address the most immediate concerns. Simultaneously, I would remove the aerators from each faucet, as well as the shower head, as they are very possible crudded up, and the contents may provide some evidence of where the probloem lies as well.
 
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Old 08-16-13, 05:56 AM
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Pressure

I hope we are not confusing pressure and rate of flow.

Check rate of flow near where the water service enters the house and compare to an upstream location the greatest distance away from the entry point. If you find a significant difference, your pipes are clogged inside the house.
 
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Old 08-16-13, 10:29 AM
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What exactly is the difference between pressure and rate of flow? Are there different gauges for each of them?
 
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Old 08-16-13, 11:53 AM
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hi aard Ė

As you can tell Iím no expert but I think standing pressure is the pressure on the system under no-flow conditions. That would be at any point. When the water starts to flow the pressure actually drops at that point.

So with all water usage turned off in your home, if you use one of those cheap pressures gauges you can get at Home Depot etc. (link below) you can put it on a hose bib and open the valve and check the pressure. If the pressure reads good then your house pressure would seem to be OK and thus it would seem to be a flow problem caused by blockage (clogged pipes etc.).

But I thought the proper order of troubleshooting is that you are first supposed to make sure the pressure is adequate to your home before you worry about flow problems? (But I am a newbie.lol)

Thatís why I suggested (and I think why marksr did also) using a cheap gauge to check the pressure. With all water turned off if the pressure reads good then you would start to worry about flow problems through your piping.

Rain Bird 3 in. P2A Water Pressure Gauge-P2A at The Home Depot

But if the gauge reads low pressure then I believe you would start thinking about the PRV and possible adjustments or replacement. Or the shut-off valve to your home, etc.

Iím not sure, but I thought normally with clogged pipes you will see good flow at a fixture when you first turn on the water, then it drops precipitously. But as I said Iím a newbie, not an expert.

As pointed out galvanized piping is old stuff and you can see from the picture how they can clog up really bad over time. Shocked me when I removed the pipe. (new pipe left, old right).



To test rate of flow you would use a bucket and a watch to see how many gals/min you would get at various points in your system. If you saw a significant difference at (near) the point of entry into your house compared to a point far away from the entrance you would know you have a flow problem, clogged piping.

You would probably be better off if you could describe to the folks here what kind of piping you have in your home and what you have where the pipe enters your home (i.e., do you have a PRV , etc.)

p.s just remembered one more thing, I think marksr alluded to this, with the gauge on a hose bib if the PRV is bad you may likely see a significant drop on that gauge if you use water someplace else in the system. I'm pretty sure that's correct.
 

Last edited by zoesdad; 08-16-13 at 12:33 PM.
  #11  
Old 08-16-13, 06:47 PM
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I think zoesdad hit the main points. You're probably looking at either clogged galvanized pipes or a mis-adjusted or non-working PRV.

If you have a PRV, that would be my first guess, second guess is clogged pipes.

Also, regardless of your pressure/volume, sprinkler systems are designed to use most of the available water. So it's not too surprising that your inside water pressure suffers when the sprinklers are on.
 
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Old 08-16-13, 07:58 PM
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Also, regardless of your pressure/volume, sprinkler systems are designed to use most of the available water. So it's not too surprising that your inside water pressure suffers when the sprinklers are on.
Very interesting. Learn something new all the time here. That is really good to know for planning purposes.
 
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Old 08-18-13, 06:52 PM
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Zoesdad: sprinkler systems are typically designed to use as much volume as available in order to reduce the number of zones. Fewer zones mean fewer valves, less pipe, less work, and lower cost. Of course there's a fudge-factor built in, so it's not like you won't be able to flush the toilet with the sprinklers running, but you'll likely notice a difference.
 
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Old 08-19-13, 09:26 AM
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Thanks for that good information.
 
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Old 08-21-13, 12:15 PM
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So, I took a picture of a meter at the front of my house. Is this where the water is coming into the house? I assume this is the water meter and not the gas meter due to the size of the pipes. Can someone confirm that?

Since I'm new to this, can someone explain what parts are what in the picture and how I can safely toy with things?
 
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Old 08-21-13, 12:58 PM
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That looks like a gas meter to me. Water meters are usually buried in the yard [to protect from freezing] with a small cover for access.
 
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