# 3/4 vs 1" water meter



## mwemaxxowner (May 30, 2020)

You all may have seen it before, but I've inherited a piece of land with an existing irrigation system.

It's currently plumbed from his old irrigation meter (they still live next door). He had a 1" meter put in, and plumbed everything with 1" PVC. Main line, laterals, everything seems to be 1".

I had an irrigation meter put in on my property, and am in the process of getting everything plumbed to my meter.

A few of the irrigation zones are now on my meter, as well as our pool house and a few spigots around our pool.

Right now, while we're in transition phase, I have it plumbed so that, depending on how I have a few valves turned, I can have all of that running off either his meter OR mine.

I have 120' of 2" line before my side necks down to 1" to meet the existing pipe work that was there. My first spigot is in the 2" main line.

Even with me running 2" pipe, and his side all 1" pipe, when I test that spigot off my 3/4" meter I only get about 7 gpm.

When I shut off my meter, and open the valves to let the system be supplied by his 1" meter, I get 10 gpm from that spigot. Where that spigot lies coming from his meter there is probably 160', to maybe 200', of 1" pipe. Coming from my meter there is 120' of 2" pipe.

All this matters to me because there are two zones of sprinkler heads that I use in my lawn from that irrigation system. It is currently only supplied by his meter. I have not yet run main line to tap into those zones yet from my meter.

I am afraid with the difference in flow, I will have trouble with my meter not driving those sprinkler heads as well as his. It uses Rainbird 5000 sprinklers, currently with 3.0 nozzles. 6 heads per zone.

I *think* I can step the nozzles down to compensate if the sprinkler performance is sub par and possibly get the coverage back up. I'll run longer to compensate.

The purpose of my post is, would it be worthwhile for me to pursue having a 1" meter put in? Will just the meter being 1" vs 3/5" truly make that much difference? Or are there perhaps other factors at play? There is maybe 1/8 mile between the two meters along the road. There isn't much difference in where they are located on the supply lines from the utility company.

If the meter being larger is likely responsible for the difference, I'll pursue getting a larger meter once I plumb my meter to the other two zones. That is IF I'm not able to get satisfactory coverage. Or, I'll split the zones up some to have fewer heads per zone. I'm just hoping to do the least amount of digging and plumbing necessary. Sod is nice and established!

We both only have 35 psi. I bet some of y'all are laughing that I'm jealous of 10 gpm. Lol


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## BadDogPSD (Jul 9, 2020)

1" is 33% larger so it should flow more. We're on a 3/4" meter, that goes to 1" and flow just under 19 gpm but our pressure is 84. I'm currently redoing our sprinkler system to address a multitude of issues and am using 2 gpm nozzles on the 3 larger areas that have rotors. I'm trying to keep the planned flow rate below 15 gpm to allow for future unknowns. 
Is 35 psi typical for your area?


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## Ware (Jan 28, 2017)

Is it a true 3/4 meter or the common 5/8 x 3/4 (5/8 meter body with 3/4 connections)?

Either way, you can use this table to compare pressure loss through different meter sizes at various flows.

Any meter size will work with the flows you're dealing with, but a larger meter will have less pressure loss at any given flow rate. Using the table, you can see a 5/8 meter has a 3.7 psi pressure drop at 10 gpm, while a 1" meter only has a 0.7 psi pressure drop at 10 gpm.

There is a lot going on, but to oversimplify it water will tend to reach the most efficient balance between flow rate and pressure loss - so less pressure loss will generally allow for higher flow rates.

When dealing with low system pressures, everything you can do to reduce pressure losses will help - but that of course comes at a cost.


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## Ware (Jan 28, 2017)

BadDogPSD said:


> 1" is 33% larger so it should flow more...


Diameter, yes, but the cross-sectional area of 1" is really more like 78% larger than 3/4" - so the increase in safe flow rate is higher than 33% more.


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## Ware (Jan 28, 2017)

@mwemaxxowner if you haven't already, I would highly recommend reading through Irrigation Tutorials. It takes some time, but it is without a doubt the best resource there is for learning more about irrigation system design. :thumbsup:


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## mwemaxxowner (May 30, 2020)

I don't know what's typical. My house reads 35ish psi, my irrigation meter reads 35 psi, and the irrigation meter next door reads 35 psi.

In a nutshell, the system performs more than adequately with the current head spacing and the gpm/pressure that it currently sees from HIS 1" water meter.

I'm wondering if simply a size larger water meter, as he has in this case, can be responsible for 3 more gpm, or the difference between 7 and 10 gpm.

I've looked at the tables. I see the theoretical pressure loss for a 3/4 meter or a 1" meter at 10 gpm or 7 gpm, but that's using gpm values that I've measured AFTER the meters and AFTER x amounts of pipe. The losses in flow have already happened and the only pressure I can measure is static.

All I know about th meter is it has a label or "3/4" on it (my meter).

I've spent lots of time in the irrigation tutorials over the last several months.

What confuses me is, it sounds like SHORT sections of pipe, particularly short sections of smaller than surrounding pipe, are ignored in the pressure loss tables. I.e. of I have 2" pipe on a main line but some odd ball section of 1" that is 6" long, or for some unknown reason a 1" valve, or whatever that the water speeds up to get by and I is negligible.

I see the meters as a short section of pipe in my mind. You have this huge supply pipe on the water company side, and 2" line on my side, and this meter that's less than one foot long that's labeled as 3/4.

Can it being 1/4" larger really be significant?

If so, I will work on figuring out what I have to do to upsize my meter so I can take advantage of more flow and the larger piping I've chosen to lay.

If I shell out a lot of money for a 1" meter, convince them to put it in (that's what he did. He bought a meter and they agreed to install it. But that was 35 years ago) and I still only have 7 or 8 gpm, I'm gonna bang my head against a wall!

I can make any new irrigation I run work to what I have. I really want the existing irrigation to work too, though.

Although, with some work it can me massaged a bit and a zone split into two and made to work too.


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## BadDogPSD (Jul 9, 2020)

Ware said:


> BadDogPSD said:
> 
> 
> > 1" is 33% larger so it should flow more...
> ...


This. Thanks for the correction. I knew something wasn't right when I typed that, but the brain just wouldn't engage!


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## mwemaxxowner (May 30, 2020)

One other thing that confuses me.

I'm revisiting irrigation school. In the design stages of the tutorial, it has you calculate your maximum available flow based on your pipe sizes. It seems it has you actually measure gpm and use that in your design as a last resort IF you can't find your supply piping from the meter, and are unsure of the size.

Is this just assuming your water source from the municipality is much better than my town and providing much more flow?

I say this because my flow is nowhere near the maximum flow rates for the size pipes we have. Not even the flow over on my neighbor's meter with the bigger meter and more flow.

The tutorial addresses this by saying there may be unknown restrictions in the pipe. If so mine has to be before the meter. Before I ran my main line I tested directly at my meter straight off the ball valve with a very short section of hose, and still only got 7.5 gpm.

This is with a brand new meter that they installed when I asked for an irrigation meter. But an old tap into the supply pipe from the road. Perhaps that old tap is corroded and restricted, but next door must be the same way. With a 1" meter he's only getting 10 gpm @35 psi.

I guess I'm puzzled why the recommendation is to build your system based on calculations for maximum flow rates based on pipe size, and not on actually measuring flow at the meter, then calculating losses from there based on pipe sizes and valves.

I'm puzzled why our water flow and pressure is so much lower. Until I came here and started learning about irrigation installation I didn't realize what we have is abnormal.


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## mwemaxxowner (May 30, 2020)

Where do you guys recommend to buy pumps from? I don't think it will be terribly hard to determine what I need in a pump if I decide to get one, but I'm sort of clueless as to where to look to select one.

I think I could get 25 psi or so to my heads, and could just space my heads 20' apart, and only run 2 or 3 heads per zone, if and when I decide to build an irrigation system on the other half of my yard.

But, the irrigation tutorial insists that you need at least 50 psi design pressure. I'm undecided as to whether I'm going to try to build a system that will work as is or add a pump.

Next door 35 psi and 20' head spacing (up to 25' in a few spots) seems to work well.


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## mwemaxxowner (May 30, 2020)

I called the man in charge of the water utilities. He said he sees about 40 psi at the fire hydrants close to me. He thinks I should see a little bit more than 30-35 but it's in the ballpark.

He said as far as me getting a larger meter, he said I have a 3/4" tap. When the old 1" meter next door was installed, he also had a 1" tap put in. So there's not much for me to gain without paying for a new tap to be put in.

He is going to check on a few things he can do for me though. He said he may be able to raise the level in the supply tank a little to get a little more pressure to me.


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## LAG Gamecock (Apr 23, 2019)

Your water pressure is pretty low IMO. If you are serious about an in-ground system, I would go with a 1in tap and 1in meter. That is where the restriction is. It is going to cost more up front but considering your watering area and distance it sounds like the best option for you. It will give you the most gpm. You will be able to have more heads on a zone which can reduce the size of the controller needed and the overall complexity of the system.


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## g-man (Jun 15, 2017)

It might be worth checking your meter. It normally has a gate valve. Make sure it is fully open.


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## mwemaxxowner (May 30, 2020)

LAG Gamecock said:


> Your water pressure is pretty low IMO. If you are serious about an in-ground system, I would go with a 1in tap and 1in meter. That is where the restriction is. It is going to cost more up front but considering your watering area and distance it sounds like the best option for you. It will give you the most gpm. You will be able to have more heads on a zone which can reduce the size of the controller needed and the overall complexity of the system.


Well, there is an EXISTING in ground system that I have no choice but to be serious about. Lol

There are a total of 7 zones currently installed and operational, but 5 of them are around our pool and are related to shrubs or small grassy areas without a ton of heads.

Two, however, are in what is now my lawn.

At the very least, I've got to get those going off of my water supply, and out of the neighbor's name.

My wife's grand dad is next door. Those zones are running off his meter. He pays it, then declines my offer to pay him back, but gives me a list of projects he'd like me to do...

Also, even with the 1" tap next door, he only has 10 gpm and still the 35 psi. Is 2.5 to 3 gpm worth $1500?


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## mwemaxxowner (May 30, 2020)

Right now those two zones run in a more than satisfactory way. The one I use the most has 6 Rainbird 5004 rotors, an average of 23' spacing, and they do spray head to head. The water distribution seems to be acceptable, just based on the fact that my sod looks good. They were an absolute life saver to run while getting the sod established.

I've yet to do a tuna can test to check distribution, but it seems to be nice and evenly healthy. I ran it 45 min per morning each day early on with my sod, then eventually worked to 3- 4 times per week. Sometimes having to run an extra day or two when it was 100 degrees.


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## Green (Dec 24, 2017)

g-man said:


> It might be worth checking your meter. It normally has a gate valve. Make sure it is fully open.


Fully open, and then a slight turn (up to a quarter turn) clockwise to prevent the handle from sticking in the fully open position. This advice came from a plumber.

New homes may have a ball valve as the main shutoff instead.


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## mwemaxxowner (May 30, 2020)

Mine does have a ball valve, and it's fully open. Our water just sucks! Lol


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## mwemaxxowner (May 30, 2020)

I currently have this 12 zone controller, but I'm only using 2 zones from it.



I also have this 8 zone controller not in use, but it's functional.



I'm not so much concerned about having multiple valves to control and a controller to handle them, as I am being able to reasonably get enough water down without the system having to run crazy long run times.

I have roughly figured my pressure losses and whatnot on the path I want to run my pipe, but I've yet to sit down and put it all on paper and run it through the spread sheets.

I don't have a computer, and those programs won't run on mobile spreadsheet apps.

It seems like, with the use of all 2" pipe as my main line, and 1" laterals or even 1.5" laterals, I can preserve nearly all of that 7.5 gpm and get at least 25 of that 30 psi to the sprinkler heads. I have plenty of time to work on planning it out. And I'm going to tap into the existing system first and see how well it drives those 6 head zones and play with some nozzles on them.

I think Stryker recommends not to use lower than 2 gpm nozzles except in corners, so I want to sketch it all out and see where I need to use what nozzles and go from there.

I think I can average 3 heads per zone as is.

In the irrigation tutorial, it touches on booster pumps and determining what you need in a pump, but only very briefly. I'm fully willing to buy and install one, but I don't see much about them on this site. I'm not real sure where to look to find a good one, and a Google search so far hasn't helped a ton.

I have both 220 and 110 power available pretty close t to where my main line runs by the pool house.


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## tjcarpenter1 (Apr 17, 2020)

mwemaxxowner said:


> I currently have this 12 zone controller, but I'm only using 2 zones from it.
> 
> 
> 
> ...


I found this thread, and it is similar to my situation. Im curious what you ended up doing with your system


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## mwemaxxowner (May 30, 2020)

So far, nothing. I'm definitely not going to upgrade the water meter though.

I think I have decided to be bull headed and put together a system that will work with this pressure and flow. On paper I can make it work, but the experienced members are telling me no matter what the charts say, they see sub par performance from rotors that don't have 40+ psi at the head.

If that's what I encounter after trying to design my system for about 25 or 30 psi at the head I'll install a pump. I've spent quite a bit of time looking at pumps too.

The thing holding me back is I really detest the idea of having to use electricity AND water to water my lawn. The water bill is already through the roof.

For now I'm using two traveling sprinklers (orbit lawn tractors). They work really well and get a better distribution of water than the network of hoses, timers, and impact sprinklers I used last year.

It's not as convenient, as I have to manually set up my "track" with the hose each time, but I have the route the tractors need to run pretty well dialed in, so it's a minimal burden .

Even with my low pressure, they will throw 50' in diameter, so they cover a lot of ground as they operate. Since they move forward slowly as they water, any uneven distribution of water throughout the throw of the wands is compensated for perfectly.

The second one I have I bought for $50 from tractor supply.


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## MasterMech (Sep 24, 2017)

mwemaxxowner said:


> So far, nothing. I'm definitely not going to upgrade the water meter though.
> 
> I think I have decided to be bull headed and put together a system that will work with this pressure and flow. On paper I can make it work, but the experienced members are telling me no matter what the charts say, they see sub par performance from rotors that don't have 40+ psi at the head.
> 
> ...


Curious, how long is each track and what kind of hose are you using for the tractors?

Briefly reading through your prior posts, faced with a maximum pressure of 35psi static, 7 gpm, and attempting to run rotor heads, a booster pump would be a big yes from me. I'm surprised your happy with RB5000's with only 35 psi of what I presume is static pressure. The pump would eliminate the need to oversize your mains and laterals so much and significantly reduce your watering time. Not to mention how much overall piping and valving (less digging too!) it should save not having to design such small zones. Less hardware in the ground also means fewer oopsies when digging for future projects too. To buy all of the hardware, dig all of the lines, and then admit defeat and install a booster pump would be a shame.

With 35 psi, I'd be looking to boost the pressure in the house too, and that's coming from a guy who had well-water for 30+ years.

As far as the running costs go, I'd go with a good weather-aware smart controller (Rachio, rain machine, yardian, etc) to minimize system usage.


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## mwemaxxowner (May 30, 2020)

How would a pump reduce my watering time? It is my understanding that a pump will not increase flow, only pressure. Seems watering time would be the same. I would still have 20' head spacing, and still only 8 gpm before any losses. Same approximate time running per inch of water, no? Just now with better sprinkler performance and proper atomization of the flow from the head.

Increasing pressure but not flow is only of minimal benefit, I'll still need a boat load of zones and still only be able to run 3 heads per zone in most cases. And, like I said, then I'm running my power bill up as well as water bill. I'm afraid the power bill would increase quite a bit, as I would have to run it for quite a while with such low gpm, and so many zones.

Other places in town have to use pressure reducing valve, and they aren't sure why my pressure is so low, but I've called everyone up to and including the mayor and have gotten nowhere.

I don't think I'd reduce my pipes or valves much at all. With the layout of where most of this goes, it's either throw 20' or throw 40'. I asked about that a while back and they said that these rotors don't do well at 40' spacing.

If I could increase my flow (I've been told many times over that a pump will not do that for me) or if I could throw 40' as opposed to 20, then I might be getting somewhere.

I have two 150' runs of zero g hose on opposing sides of my driveway for my traveling sprinklers. I ran 200' at my old house.


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## MasterMech (Sep 24, 2017)

The pump will not increase the total available supply but it will let you use more of it. If you get 7 gpm at 25 psi from your supply, maybe you can get 15 gpm @ 10 psi. 10 psi isn't going to run your irrigation system very well but the booster pump would let you run that 15 gpm at 45-50 psi instead of 10. A decent sized pressure tank in the house, a 40/60 pressure switch and you'd be living large enjoying higher water pressure EVERYWHERE instead of just for the lawn. I know my wife wouldn't be happy with 35psi. :lol:

What is your elevation in relation to the rest of town? Relatively high?


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## mwemaxxowner (May 30, 2020)

I don't understand what you just said at all. Lol.

But I'd like to!

How are you getting that I could have 15 gpm and 45 psi with a pump? Both on this site, and several pump manufacturers I've asked have told me all I would get is still the same 7-8 gpm but more pressure.

My elevation must be higher but the town is relatively flat. It can't be much difference, but I live in a Podunk town that's stuck in 1980 also.

I'm not arguing with you! I'm just trying to get to the bottom of these bits that I don't seem to understand.

I've gone so far as to contemplate the possibility of having a holding tank and a pump that feeds from that so I can have whatever pressure and flow my heart desires. But then I decide that I don't care enough to go through all that.

We've gotten used to the pressure in the house. My wife doesn't desire to spend any money to improve it. We had outstanding pressure at my old house though. I never tested it but it would blow a cup or a bucket out of your hands outside if you turned it on too strong too fast and weren't prepared, and it would blow holes in water hoses. We do miss it when we take showers but that's about it. Otherwise it's adequate.

I keep hoping that they continue improving the infrastructure around here and eventually the town will make updates that improve my pressure from the supply.

I wouldn't dream of buying much PVC right now anyway!


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## mwemaxxowner (May 30, 2020)

The topo map looks like everywhere in town is 600'.


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## MasterMech (Sep 24, 2017)

@mwemaxxowner

Does this help?


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## MasterMech (Sep 24, 2017)

The above makes quite a few assumptions about pressure loss through piping but should illustrate my point on what a booster pump would do to your system design. Twice the number of heads running at proper pressure. Heck, if your piping losses are low, you might need a PRV with the 1.5 HP pump, or could downsize it a notch. (or add heads!)


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## mwemaxxowner (May 30, 2020)

I still don't understand how it extracted 16 gpm from a supply with 8.

I keep being told a pump wouldn't allow me to get any more gpm than what I already have past the meter. I keep finding that it won't draw any more flow through than I already have.


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## MasterMech (Sep 24, 2017)

mwemaxxowner said:


> I still don't understand how it extracted 16 gpm from a supply with 8.
> 
> I keep being told a pump wouldn't allow me to get any more gpm than what I already have past the meter. I keep finding that it won't draw any more flow through than I already have.


They would be right if that 8 GPM used all of the available pressure from the city main but since you are stating that you get 8 GPM @ 30 psi, this tells me there's more flow available, just at a lower usable pressure.

Think of it like this, you can get more than 8 GPM past the meter, but not at 30+ psi. You must have that 30 psi "reserve" to operate your sprinkler system. If you no longer need that 30 psi then you can pull more flow (at lower pressure) until you completely max out the meter capacity. You just need enough pressure to get water to the pump, where you're going to boost it using external energy, electricity in this case.

You can demonstrate this to yourself if you've already built the bucket test rig from irrigation tutorials. With your valve closed, the pressure gauge will read whatever your static water pressure is. 35 psi if I read your posts right. Open the valve until it reads 30psi, you'll get xx GPM. As you continue to open the valve, the pressure gauge reading will drop but the flow rate will increase.


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## mwemaxxowner (May 30, 2020)

So, if I understand this correctly, if I were to install a pressure reducing valve I would actually get more flow from the meter?

Yes, the pressure readings I've given are all static.


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## mwemaxxowner (May 30, 2020)

I would guess when the spigot is at full open I don't have much dynamic pressure, but at that time only 8 gpm.

So I guess, why I'm still confused, I'm not getting 8 gpm at 35 psi, since that is the pressure at static when there is no flow. I'm getting 8 gpm when the spigot or a valve is full on and there is less pressure in the system. I don't have any way to measure the dynamic pressure.

My 8 gpm figure on the irrigation meter was tested with a ball valve directly at the meter adapted to about 2' of 3/4" hose.

If there is a valve directly at the meter full open giving me x gpm, I can't understand how it would do any more. It seems apparent to me that's all the flow the meter has access to.

I'd love to be wrong, and I'd also love to be able to test that out somehow.


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## MasterMech (Sep 24, 2017)

mwemaxxowner said:


> I would guess when the spigot is at full open I don't have much dynamic pressure, but at that time only 8 gpm.
> 
> So I guess, why I'm still confused, I'm not getting 8 gpm at 35 psi, since that is the pressure at static when there is no flow. I'm getting 8 gpm when the spigot or a valve is full on and there is less pressure in the system. I don't have any way to measure the dynamic pressure.
> 
> My 8 gpm figure on the irrigation meter was tested with a ball valve directly at the meter adapted to about 2' of 3/4" hose.


Then you will indeed only get 8GPM from the system. Without a booster pump, you won't even be able to use all of that 8GPM.

All you need to measure the dynamic pressure is a pressure gauge in-line ahead of the ball valve.


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