Dad has a ? about new water main

   / Dad has a ? about new water main #1  

Richard

Elite Member
Joined
Apr 6, 2000
Messages
4,997
Location
Knoxville, TN
Tractor
International 1066 Full sized JCB Loader/Backhoe and a John Deere 430 to mow with
My dad sent me an email. I've copied it below. My dad's comments are in blue and his plumbers comments are in black. The plumber is talking about the city engineer. Seems the engineer and the plumber are telling dad conflicting stories (as best I can tell). I told dad I'd put it here, to the Board of Experts for their thoughts. The house in question is my dad's mother in law's house. It's currently on a (weak) well and now that the area has grown, he's thinking about either attaching to city water OR, deeper well, or draw irrigation water from the lake. To get water from lake, it would have to cross "other" property, which as I understand it, is my dad's wife's sisters property.


Hi Richard,

The enclosed is from plumber who has done some work for us at park and house in Lexington. Working on plan for some things at the house to modernize (like get rid of lead/rusted pipes and more capacity so can sprinkle etc and probably get now available public water as deeper well may not do anything anyway).

House about 350 ft from water source. 3/4 meter costs about $2,000, with one inch double that. Unsure cost of of l.5 or2 inch.

Water company guy indicated to me over phone that is use, say l.5 or 2.0 line from meter to house you will have plenty of water and pressure despite use of 3/4 meter. It appears kim disagrees. I somehow agree with Kim because : if X (amount of water through a 3/4 pipe) enters Y (2 inch line with much more volume to fill) you would gradually, I assume, see the 2 inch line not be full. But again, maybe I am missing something as I kind of think water guy lead me to believe you would not lose discerible pressure in the 2 inch line. What about lose of volume--or would that be slow enough you would never know unless it ran all day?

Any thoughts???? To get some water from lake would need to pump up hill and across other property.



Hi and Good Evening

What the engineer is trying to tell you is..........in common knowledge would be something like this, have you ever had good water flow at a hydrant and put about three hoses together, and when you tried to use it only had a trickle at the outlet end? There is so much resistance along the walls of the hose of that small size, the pressure is there, but you have no volume.. Or maybe you have ran a hose connected to a hose to a garden, when you get out there, no flow, this is kinda what he is telling you.

By the use of the high capacity 3/4 water meter at the road, or source of water connection and supply, and by using a larger line to reduce friction in the pipe to the home, yes you will obtain adequate, and quite good water flow to the house, as this is right at 350 feet when I measured it, the line would have to be bigger, a 3/4 line would have no flow at the house, just like the hose I am talking about at the top of this page. However only so much water can get through a given size opening at a given pressure, and the water main will hold at what pressure? whatever it is it will be even and steady, and without getting into a lot of technical stuff, an 1 and 1/4 inch line is all that is needed for the 3/4 meter, 3/4 is 3/4 and only so much flow can come through it, no matter what some engineer says!! An exaggeration of this so you can picture it is put this 3/4 line into a six inch line , turn it on and watch, flows along the bottom of the line, the rest of the space is wasted, similar, not exact, but helps you understand.

Now bottom line is an 3/4 high capacity water meter at the water connection source with an 1 and 1/4 inch water main to the home will be adequate for serving the home and a couple standard yard hydrants along the way, especially as the yard hydrants will normally never be on when one is using the water in the home. HOWEVER IF YOU EVER DO WISH TO USE AN AUTOMATED SPRINKLER SYSTEM, TIE IN THE REQUIRED BACKFLOW DEVICE THAT IS REQUIRED AND PUT IN ZONES TO PUT IT BLUNTLY YOU ARE STANDING DOWNSTREAM OF THE COW WITH A 3/4 METER. IT SIMPLY WILL NOT ALLOW THE VOLUME NEEDED FOR A MEDIUM TO LARGE AUTOMATIC SPRINKLER SYSTEM-ADEQUATE FOR THE HOME AND A COUPLE SPIGOTS-I AGREE-SPRINKLERS NO!!!

Finally another consideration would be........money and cost, this and that........how much would it cost to deepen the well and or dig a new one, and is it possible to get enough flow for sprinklers if you wish to do so, or you can always pull water from the lake for sprinklers, pulling from the lake, depending on if you can run across, would naturally be more cost effective than city water, not only the meter fee, but long term in water usage fees.

Hope this helps you , I am looking at the entire situation, and if you can get permission to run a line from the lake, later, for sprinklers, I will agree with the engineer. If you have to use city water for automated sprinklers, or plan to, I do not agree.
 
   / Dad has a ? about new water main #2  
Our meter is probably 400' from the house. The water line from the meter to the house is 3/4" PVC. We've never had a water pressure problem. With a sprinkler system, I don't know.

What would have a lot to do with it would be how much pressure you are starting out with. I checked the pressure at the house with a pressure gauge and it runs 90+ PSI.

If my memory serves me correctly, a 3/4" meter has a capacity of 15 GPM. If his use will exceed that, he'll have to increase the pipe size and run off of 2 meters.
 
   / Dad has a ? about new water main #3  
We have a water meter with a 3/4 inch outlet, then goes up to 1.5 inch pipe for the run to the house ( 300 feet or so ) , then steps back down to 3/4 in the house. That was the setup recomended by the plumber who put it in and by the water district. We have plenty of water pressure and flow.

Regarding the sprinkler system, is this for fire suppression or watering the lawn or what have you?

If its for watering the lawn, etc:

You would have to see what gallons per minute flow you were getting at the house from the new pipe, then size your sprinkling zones ( and the number of sprinker heads ) accordingly to that gpm you have available.

If you need a large volume of water for field irrigation, your normal rural water pipe isn't setup for that amount of volume, the idea to draw water across the other property from the lake is likely much more feasible and economically reasonable.
 
   / Dad has a ? about new water main #4  
I think everyone agrees including the engineer and the plumber, the 3/4" meter will give a certain max flow depending on main pressure. From the meter to the home you will have head loss depending on the size of that pipe. A big ol' 6" pipe will allow nearly the full flow to pass while a 3/4" line will be small enough to create significant losses due to friction. Water lines do not work on the weak link in the chain principle. Each element steals a little bit of energy from the water stream and the sum of these losses is what you are concerned with.

A 3/4" meter will provide plenty of flow to a residential user. We use 5/8" meters for most of our city lots. Irrigation needs and wants will bring a whole different basket to the picnic.

Your plumber and engineer are saying the same thing with the engineer being more conservative in asking for a larger pipe size as being "plenty" good enough. The engineer is not trying to minimize the pipe size but instead covering his butt with a sufficiently large pipe recommendation. The plumber is trying to cut it closer and is taking more risk. They both agree that the 3/4" meter needs to feed a line with 1.25 to 2" diameter.

Myself, I would use 1.5" line assuming no big elevation changes between the main and the home. It is a common pipe size and would be "plenty". Plenty is a good thing, cutting it close won't save you much money here.

If you need more flow than a 3/4" meter will pass then you don't get two meters, you get a larger single meter. 1" meters are pretty common for residential lots with minor irrigation. Installing larger line now, like 1.5 or 2" will allow you to benefit from a larger meter should you ever decide to acquire more flow from the main for irrigation needs.
 
   / Dad has a ? about new water main #5  
Highbeam said:
If you need more flow than a 3/4" meter will pass then you don't get two meters, you get a larger single meter. 1" meters are pretty common for residential lots with minor irrigation. Installing larger line now, like 1.5 or 2" will allow you to benefit from a larger meter should you ever decide to acquire more flow from the main for irrigation needs.

I guess bigger meters are common for residential but not here (rural water district). In order to get a larger meter you will be billed at a commercial rate. two 3/4" meters are half the monthly minimum than one commercial but the same price per thousand.

Water pressure has a lot to do with this scenario. So I take it the plumber and the engineer knows what's going on here. No one here could possibly give you an answer cause we don't know the whole story.
 
   / Dad has a ? about new water main #6  
Based on the distance, IMO anything over 1" is overkill. You get something like 40 gpm out of a 100' long 1" PE line @ 50 psi. That's using the friction loss, which IIRC is about 7 psi/100'. So check the pressure at the 'curb'.

The amount of money, $2000 or doubled, may be for the use of copper. PE pipe in a 500' roll is way less than copper and saves all the additional fittings (every 100') and their pressure losses, labor to install and cost.

And if he simply must go larger ID, get 1.25", or 1.5' PE.

I suggest 160 psi or 200 psi rated PE and SS insert fittings using double opposed SS clamps per fitting. Many/most water wells are installed this way and so is my 1953 house on city water. And if he uses the lake, his house will be too....

Gary
Quality Water Associates
 
   / Dad has a ? about new water main #7  
"You get something like 40 gpm out of a 100' long 1" PE line @ 50 psi. That's using the friction loss, which IIRC is about 7 psi/100'. So check the pressure at the 'curb'."

The loss of 7 psi per 100 feet is making some assumptions. There must be an assumed flow rate for thi 7/foot figure. Is it 40 gpm or the 15 gpm? Big difference but head loss is based on velocity.

If line pressure in the main is 70, pretty typical, then after 300 feet your house will only be getting water at 49 psi. But then there's all the BS copper fittings and pipe size reductions in the house and you could easily loose 10 more psi before spraying out the nozzle at 39 psi.

I don't think I would be willing to lose 21 psi for the small price difference. I very much agree on using the rolls of PE tubing. Good stuff.
 
   / Dad has a ? about new water main #8  
Yes there is a flow rate, I mentioned "something like 40 gpm", meaning I am not sure of the 40 gpm figure (it may be 37 gpm at 50 psi). And what I meant by "That's using the friction loss, which IIRC is about 7 psi/100'" was that the friction loss was already suffered giving you 40 gpm (that's open discharge) at the other end of the 100 foot. I was/am relying on my feeble memory so, sorry for any confusion. The question here is what ID to use and it is Richard's (elderly) Dad and I assume a limited budget.

For this application, 350', 1" through a 3/4" meter will supply a 2.5 bathroom house and irrigation, no? That assumes proper street pressure; like you say, 90 psi. IMO anything larger than 1.25" is overkill; and that would feed a 3.5 bath house with sprinklers; using PE tubing.

For quick reference, I have a few web sites I use for these things, here's a friction loss calculator for PVC and fittings. BTW, in sizing this, the psi and ID of the line establishes the velocity; or I don't understand what you mean by "....but head loss is based on velocity.". Could you explain?

http://tinyurl.com/n6uf7

Here's a friction loss chart for PE pipe.
http://tinyurl.com/dkeen

Gary
Quality Water Associates
 
   / Dad has a ? about new water main
  • Thread Starter
#9  
Thanks for all your thoughts. I'd checked back earlier but we just got back from my wifes aunt's memorial services. (happened to be here on the farm so the entire family & extended members were over & just left)

I'll send the above comments to dad tomorrow.

:)
 
   / Dad has a ? about new water main #10  
""....but head loss is based on velocity.". Could you explain?"

To have a head loss due to friction you have to have motion. It is a dynamic loss. If you have no flow you have no velocity and no pressure loss due to friction. In the no flow case, even a tiny 1/4" line would provide the full pressure from the main to the home. The losses happen when you try and get flow.

I would agree that 350' of 1" PE line, 90 psi in the street, 3/4" meter, and 2.5 bathrooms with no needs for future expansion would be a fine system. If my elderly dad asked for the minimum pipe size for adequate performance the above system would be sufficient, even pretty good. If my same old dad wanted to irrigate from this service then it would be wise to consider the cost to upsize the line vs. more zones of the irrigation system.

I think we are saying the same thing Gary. There is the minimum vs. plenty.
 

Tractor & Equipment Auctions

2021 FORD F-150 XL EXT CAB TRUCK (A51406)
2021 FORD F-150 XL...
2014 Chevrolet Spark Hatchback (A50324)
2014 Chevrolet...
Agrotk 72" Skid Steer Broom, New  (A52384)
Agrotk 72" Skid...
2022 Chevrolet Tahoe FL SUV (A51694)
2022 Chevrolet...
2016 Ford Explorer AWD SUV (A50324)
2016 Ford Explorer...
80in HD Tooth Bucket with Side Cutters ONE PER LOT (A52748)
80in HD Tooth...
 
Top