Hi,

I'm in the early stages of determining what type of sprinkler system I might want to install. Recently, I took PSI readings at my two outside spigots and had two different readings. The one closest to where the water line enters the basement gave a reading of 40 PSI. The other spigot, located diagonally opposite, had a reading of 48 PSI.

The house is only six years old, has PEX piping throughout and the two spigots are at the same elevation.

Any thoughts on why I would get two different PSI readings when all the faucets and appliances that use water were turned off?

Thank you for reading,

John

Trace your piping to make sure both fixtures are plumbed off the same side of your PRV. It is not uncommon to have one branch off the the main before the PRV, and the other one after. That could explain the difference. Another check would be to put a pressure gauge on the one reading 40 psi, open the valve, shut off the house main (with no water being used) and see if the pressure drops, that would indicate a leak behind the wall.

NO. If they are on the same elevation and there was no water being used, they should be the same, and if water were being used, the one on the far end should have been the lower pressure.

NONE of that would explain a HIGHER reading at the far end of the house.

Verify the gauges read correctly - at least compared to each other. Switch gages between the two spigots to see if the readings stay the same with each gage.

Thanks for all the responses. Here's some replies to the thoughts and suggestions.

I used the same gauge for both spigots. Checked one closest to where water enters the house, read 40 PSI. Turned that spigot off and checked at other spigot, read 48 PSI. Then I did it again because of the pressure differences.

There are no branches off the main line before the PRV. Also, it was suggested above to turn on first spigot and then close the main line coming into the house. The gauge stayed at 40 PSI.

Is it possible that because the spigot that reads 40 PSI is used more that there could be some mineral build up that would cause it to be less? I wouldn't think that would impact it, but not too much surprises me anymore.



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When testing static pressure(no water flowing), the only thing that should change pressure is a change of elevation of the test points.

About the only thing that impacts "static" pressure is a height differential. It is unaffected by "build up, pipe sizes, or any other factor that affects dynamic pressure.

I guess the house isn't as level as I thought even though both spigots exit the basement at the same distance between the top of the foundation and the side of the house.

I appreciate the responses to my conundrum. Regardless of the differences in the pressure, it is still strong enough from both spigots to satisfy what I need for my DIY sprinkler system.

Thanks,

John

John, you lose .433 psi for every foot of rise, so if you have an 8 psi difference, that equates to an elevation difference of about 18½ feet.

Time how long it takes to fill a 5 gal bucket. That translates into gallons per minute. Each emitter you use will have a flow rating. You have to maintain a pressure at combined flow, and only you know what that is.

To have an 8 pound differential, the back one would have to be almost 18 feet LOWER than the front one.



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what does that have to do with his question about a pressure differential?

"Regardless of the differences in the pressure, it is still strong enough from both spigots to satisfy what I need for my DIY sprinkler system"

That was in response to his question.

More than 18 feet lower? Wow! I'm confident it's not off that much. Though I'm now even more curious to find out why there's a difference.

As to the DIY sprinkler system that I'm pursuing and why the pressure will be enough, it's because I'd only be running one sprinkler at a time from each spigot. While I'm not using this exact same setup, mine is similar and will serve my needs while saving a lot in installation costs of a standard system. [www.wateringmadeeasy.com]



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The link does not show anything useful, but there are specific requirements when you connect a sprinkler to a hose faucet but we cannot tell if you are doing it correctly.

hj,

I've updated the link above, hopefully it works now. As you can see, it is basically the same thing as having an above ground sprinkler. It's just inserted into the ground to avoid having to move the sprinkler when mowing or the kids are playing.

I also have a backflow preventer that I'll be attaching to the spigot as a precautionary measure.

Now, there's something that makes no sense to me. If I have to walk to a permanently installed sprinkler with a hose, I might as well carry a sprinkler with me. And the same for disconnecting it. I'm sorry, the best marketing in the world couldn't make me need that.

$3,500 + annual maintenance charges for a professionally installed system vs. $150 for a hybrid system that allows me to set the range of coverage and not worry about it being bumped out of alignment by a toy, dog or kid. And, where I don't have to constantly remove the sprinklers to mow or so the kids don't trip over them while playing. Plus I have a timer that controls 3 hoses. Drag them out at night, they run around 5 am and pull them back in before leaving for work. Is it perfect? No, but it's a heck of a lot cheaper and will do a good enough of a job for over $3,000 less.

John

If you can water by just putting the sprinkler in 3 places, you do NOT need a $3,500.00 sprinkler system. $150-250 maybe.