Water main question

SCOUT5

How many residential homes will a twelve inch water main service?
These are standard three bedroom two bath homes.

Smitty500mag

A fair size subdivision. 

festus

Depends on the size and elevation of the storage tank.

toad67

After working in the water industry for 32 years, a 12" main is too large for a residential subdivision, and are generally installed on main roads that the neighborhoods come off of. 12" and larger mains are generally considered a transmission main and are installed to provide adequate flow to a larger area, but generally not for domestic service hook ups. Most all of the subdivisions that were in my district had 6" and 8" mains running thru them, with the concern being adequate fire flow. Some of the smaller streets had 6" lines going into them, with a fire hydrant and then going down to 4". The problem with large mains is that you don't get enough flow and the chlorine residual dies, and then you have regulatory sampling, and water quality (taste and odor) issues. 

SCOUT5

I do not live in the city limits but my house is connected to city water and sewage.  When the system was installed (before I purchased) it was not installed to code.  The Sewer and water lines are to close to each other.   I've been in litigation over this when I had to intervene in a law suit between the city and the man who installed the system and built several of the houses connected to it.   They were trying to settle with each property owner being  responsible for the  line maintenance on their own property.   A large part of this system runs through an easement on my property.   I was not going to be responsible for other people's water and sewage.  That was corrected, but as I was the only property owner that hired an attorney and protected myself.  I knew this issue had to be corrected at some point.

Forward to now.   The city sold the water system to American Water.   American water wants to fix the water system but says they can not use the existing easement because 1) both the water and  sewer lines would also have to be relocated in order to get the proper distance between them and 2)  there are issues with the easements on other's property where the lines run.

American water wants a 20' perpetual easement onto my property that borders state hwy 62 to run a twelve inch main.   It seems to me a twelve inch main is a lot of line and I suspect they are wanting to run onto a proposed subdivision east of me.  Though that subdivision could have water access from another road.     Then the water company wants a 20' easement extending north in to my property, I assume to allow me access to hook ups for the five building lots I have.   I need some written guarantees on future hook ups and reasonable access for those lots.  I also need the easement extending north onto my property to be located west of the easement proposed by them.

So, if I know how many units a twelve inch line can service I'll have a better idea of what their needs are and it may make it easier to get what I need.   This is fairly simple stuff but when you are dealing with people setting in offices looking at plat maps and areal views instead of walking the property it gets more time consuming than it needs to be.

SCOUT5

Thanks for the answers.   There are less than 30 houses currently on this system and about 12 lots that could be built on.   What I suspected is probably accurate.   They need the easement.  I'm not looking to gain anything other than what I have already agreed to, my home water, five additional hook ups and the system maintained.   I also need to hook ups to be available within reasonable distance to my lots.  Having the water system moved and in code is advantageous for me and I want to work with them to get this done, I also want what I listed.

select-fire

Well you of course can sell them the easement ..at your price

bpost

My business partner in Alaska owned a lot of property dealing with all manner of legal issues.  His wise words to me is to grant and easement the same day hell freezes over.  He was adamant on NEVER granting an easement on any of his properties.  They could buy the land for big $$$ or run their lines, poles, or what ever someplace else.  He never lost a single battle over granting and easement.

SCOUT5

If they just wanted an easement onto my property we would discussing dollars.   However I need this system fixed to protect my investment in the building lots.   It's a win for me if the system is correct.  One of the lots has state highway frontage and is zoned light commercial.  If I can get my access addressed like I want that will equate to dollars in my pocket.   I may build on these lots myself, I may partner it out, or I may just sell the lots.  What ever I do they will move easier and I will be able to get full value with the water code issue resolved.  

hobo9650

A 12 inch water main at 100 psi will flow 444 gpm.  Our water main runs well over 100 psi.  Average family will use 5,000 to 6,000 per month.  444 x 60 per hour is 26,640 x 24 is 639,350 gallon in 24 hours x 30 days is over 19 million per month.

The above show max capability and not slow flow.  I doubt the 444 gpm is a correct amount, but google says it is.

toad67

It's hard to answer your question about how many connections it will handle, when we don't know the size of the connections. Are they standard 1" residential services, some with irrigation, or are they commercial services with 2" or larger meters? Every foot of 12" main has just under 6 gallons of water, and the average household uses about 110 gallons per day. So take a 2,000 foot long chunk of 12", it holds 11,700 or so gallons of water. So as you mentioned, with 42 service connections using 110 gallons a day, or 4,620 gallons, it would take almost 3 days to turn the line over if it was a dead end. If you were one of the first few connections on the line, then you would always have fresh water. But, the farther down the line you get, the worse the water quality gets. If the line continues on to other users, then things would probably be better. Water temperature, and the process of treating it also affects the water quality...
As for the separation guide lines that you are referring to, yes, there are requirements, the depth and separation, as well as being parallel or perpendicular to each other determines the space needed between them.

love2shoot

Side question:  Is there anyway to increase water pressure using a drilled well and submersible pump?

pulsarnc

Water pressure is generally controlled by the pressure switch settings . It also depends on the horsepower of the pump And how many gpm’s you at looking for

chme

I think the 444 gpm at 100 psi is a WAY, WAY low number.  My fire pumps would push 1500 gpm thru much smaller pipe.  You may have slipped a decimal point.  Pressure from a well would be controlled by pressure switch- pump pushes water to pressure tank until switch says stop, starts pump when switch says go.  Unless you are exceeding capacity of pump. 

EW0302

My flow charts only go to 8" but an 8" pipe can flow more than 1,200 GPM and not exceed the velocity recommendations.  I would obviously presume a 12" pipe could flow much more.  Most main distributions use level controls to fill a storage tank and then pressurize with gravity (a water tower) or pumps employing variable frequency drives to vary the speed of the pumps in order maintain a constant pressure at variable flow rates.

asop

As mentioned, all depends on the gal./min. & pressure available.

Horse Plains Drifter

Yeah, I have a 400 gpm pto driven pump. It has a 4" inlet, and a 3" discharge.

Using EW0302's calculations for an 8" pipe, a 12" pipe would flow 2700 GPM.