Water meter sizing and how it affects WH tank output

thelexJanuary 11, 2014

Our community is having all the water mains replaced. They are woefully undersized at 4" so they're digging up the streets and going to a 8" line.

As part of this project, they're running new service to each house in the community. They're also installing water meters. Previously no one was on a water meter here. You should also know that the community has separate water supplies for domestic vs irrigation water. The water meters are to be installed only on the domestic water supply.

The problem is, the HOA has decided in its infinite wisdom to install 3/4 inch water meters on the domestic supply. They claim that because this is for domestic water only, there should be more than adequate pressure. They are quoting a flow rate of 30 gallons per minute at 50-60 psi via an adjustable regulator.

The old 4" water line with no meter to the house had 85 psi.

Our single story ranch style house is 5 bedrooms, 4 baths with two laundry rooms. We have multiple head showers in one master and a large 120 gallon tub. If we have one or three showers going at the same time or even with a dishwasher in addition, are we going to have adequate water pressure? We will be installing two 75 gallon WH's, one on each side of the house so that each WH supplies one side of the house.

My contractor thinks that the 3/4 inch line coming in from the meter is likely too small for our needs. But the HOA maintains that it should be more than adequate and is not willing to upsize the meter for us. Thoughts?

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If all the showers plus additional water is used at same time,pressure will drop which isn't all that bad until somthing turns off causing pressure increase and tempature change in showers. There is no reason you souldn't be alowed to pay extra for a 1 inch meter and 1 inch line. Ask them. Better still ask your water supply company.

    Bookmark   January 11, 2014 at 11:31AM
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This is where it's complicated. Our community is in essence our own water supply company. We buy the water at wholesale rates from the county. We never even had water meters in the past, but with the upgrade to the community potable water supply, it's required by law to have a meter installed even if we don't read them.

It's the HOA that has made the determination that a 3/4" water meter is adequate. The quoted output is 30 GPM at 50-60 PSI.

    Bookmark   January 11, 2014 at 4:18PM
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Well I will take you at your word that it's already chiseled in stone, so you have no options. I'm not there and you are so I trust you when you say you understand all the ins and outs but I will tell you I have never heard of a residence served by a 4" 85 psi water line. That's adiquate for several houses. I double checked on what country you live in that tolerates such hardnose approch to spending other peoples money. Seeing you live in USA,has me wondering if you took time to read the bylaws of your HOA. I don't mean to be rude but I think you are believing some inacurate information and misunderstanding some other. Were I actualy stuck with exactly what you say,I would; A. Increase line size at first point it was my option unless line size in the yard and house is regulated. B. Install a good quility pressure regulator set below main line pressure. C. Install an air charged surge tank. D. Attend HOA meetings to see what else is brewing and possibly change an officer or two.

    Bookmark   January 11, 2014 at 5:48PM
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There is a regulator at the lot line dropping the 85 psi down so that we don't have plumbing problems. Sorry, I forgot to mention that. And the branch line coming off the 4" main is much smaller - I'm not sure of the size but it can't be much more than 1" I would think.

The new main is going to increase in size from 4" to 8" with a branch line coming in. That will enter a new backflow device (something we now don't have) and a new regulator set at the aforementioned 50-60 psi with a flow rate of 30 GPM.

I just got back from a water board meeting at the HOA and this is what we were told.

    Bookmark   January 11, 2014 at 6:22PM
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And if you think that individual billing, in addition to those already "included" in your HOA fees, are far behind, guess again.

    Bookmark   January 11, 2014 at 7:33PM
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Portions of California's Central Valley area have historically not had residential water meters. It makes no sense, it's an area of dry hot summers and high per capita water use (besides the ag usage, which is the largest piece of the pie)

Snoonyb, what's wrong with paying for what's used? Everything else works that way.

    Bookmark   January 11, 2014 at 11:42PM
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"what's wrong with paying for what's used? Everything else works that way."

There is nothing wrong with it.

It's the "poor me" political process.

    Bookmark   January 12, 2014 at 1:11AM
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I don't want to get side tracked on this issue, but our community buys the water from the water district at a wholesale rate and passes on the savings to its members. The ONLY reason water meters re being installed is because this is now codified into the regulations by the water district. There is no intention to bill each house individually, but the board does have that power, although it would be subject to immediate recall if that were to happen. This is an extremely tight knit community with mult-igenerational residencies.

    Bookmark   January 12, 2014 at 2:42AM
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I have been in the water business for 15 years. It is required that all water services have a meter on them. Even if it's not billed. It is used to account for water used versus water pumped.

The vast majority of the water meters I have installed were 3/4 in. These will provide enough water for most residences. The really large houses will sometimes have a 1 inch meter but never larger than that. What size water service line do you have now? Also, most folks don't wash clothes, dishes, and take a couple of showers at the same time.

BTW, 4 inch mains are not suitable for fire protection so many water systems are replacing them. This should help with your fire insurance.

    Bookmark   January 12, 2014 at 7:42AM
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jacalhou you are exactly right. The 4" water mains are inadequate for fire protection. That's the biggest reason for the upgrade.

I'm not sure what size the existing service line is right now. We're not living in the house right now.

My concern is we have triplet boys who are now toddlers, but when they get older there's going to be 3 showers going on at the same time, will we have enough water?

Based on what I've read so far, this would could be more of a problem with a tankless unit asked to deliver a 70F water rise in temp during the coldest part of the winter, rather than during the warmer months since those units restrict flow as the temps drop as they are asked to deliver a bigger water temp rise.

But we're getting two 75 gal tank WH's so I'm hoping their reserve is more than enough for the kids.

    Bookmark   January 12, 2014 at 2:52PM
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If you already have a 1 inch service line going from the house the main then you could ask them to provide you with a new 1 inch service connection, meter and backflow device. You may have to pay the difference in cost but that should give you enough water at all times. Besides, they should try go back to the original service line size if at all possible.

If your existing plumbing and service line is 3/4 inch then going to the larger 1 inch service won't help much if any. However, it will be easier to upgrade to larger size later if you already have a 1 inch meter. Just weigh your options.

You don't want to have to get a new service tapped later after the main is buried. Tapping a water service is much easier to do when the main is still in the trench rather than buried. They'll charge you according if you wait until later.

Not trying to confuse you. Just giving options.

    Bookmark   January 12, 2014 at 10:58PM
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I'm investigating this right now, but from my conversations with the people on the "water committee" they're doing 3/4" meters only. NO other options are being offered. I forgot that the backflow device and regulator is also sized. It looks like if they don't offer an upgrade those items in addition to the meter, having a bigger pipe from the backflow device to the meter and then on to the house is moot is it not?

    Bookmark   January 13, 2014 at 12:37AM
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The backflow device is between the meter and house.

Can you find out what size service is there now?

If you can't get the 1 inch service a 3/4 inch service is used on about 85% of residences. You just have to decide when to wash clothes, dishes, baths, etc since you can't do all at once.

    Bookmark   January 13, 2014 at 4:53AM
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This is what I found out from the engineer. From the 8" main line there will be a 1" copper service line to our home, a valve, a 3/4" meter, a back flow and finally a 3/4" pressure regulator typically set at 60 PSI from the factory, that is adjustable to more or less pressure.

It is recommended that we run a 1.25" or 1.5" line from the meter/backflow device to our house.

    Bookmark   January 14, 2014 at 4:04AM
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Water meter diameter does not need to be matched to pipe diameter. Pipe diameter should be matched to water meter flow capacity. The 3/4" meter will not be a problem - it has adequate capacity for your home, provided you install adequate line size after it. Follow the engineer's recommendation for line size.

    Bookmark   January 14, 2014 at 8:24AM
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If you have a 1 inch service line there is no reason you can't have a 1 inch meter/backflow installed. The cost is a little more for the meter and backflow but it easier for the crew since all the parts are same size. They will have to install reducers and adapters to make the 3/4 meter, bf, and regulators work with the 1 inch service line. If you pay the extra cost for the 1 inch parts I'm sure somebody can make it happen.

When you make the run from the meter to the house stay away from the 1.25 inch stuff if possible. It's not very common anymore and sometimes hard to get the parts when you need to fix it. 1.5 is way more common. Bury the pipe at least 18 inches deep (about 2ft is ideal) so it won't freeze or break when a vehicle drives over it.

Once all this is swapped over and working there will be some air and discoloration in your plumbing. It's normal so just flush all your faucets and bathtubs for a while.

    Bookmark   January 14, 2014 at 12:54PM
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