Water Supply Design

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Aaron_808

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Hello again,

I am working on my addition/rebuild project and am wondering what all I need for my water supply line to my 3-bath house.

Currently I have my meter, a 40’ run of 3/4” copper up to the house, to a ball valve, to a tee leading one way to a hose bibb, another valve and irrigation, and the other way to a 3/4” pressure regulator and on into the house. There is no regulator at the meter.

I have 1” copper pipe about 5’ inside the house leading to the water softener. I’m thinking about upsizing to 1” just before my regulator outside my house for better flow.

I’m looking for recommendations before I start this work. Anything else I need here? A vacuum breaker for the irrigation system? Any specific products recommended? I will be using Aquor hydrants as the hose bibbs, which have vacuum breakers built in there.

BTW, I’m in San Jose, CA if that makes any difference. Thank you very much!

Regards,
A-A-Ron
 

Terry

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UPC code chart for California.

water-sizing-chart-terrylove-40-60.jpg


Irrigation needs either a highest point vacuum breaker or a reduced pressure double check.
 

Aaron_808

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Thank you very much for your response! I've seen you post those charts before so I decided to take a Youtube class on sizing pipes and I'm glad I did! Now I know how to use them. But I have a few questions that weren't answered there:

1. Do I need to count irrigation in my building supply sizing? My house is 39 fixture units so I'll most likely be running 1-1/4" copper to my 3/4 meter and that will max it out. I'll have a few valves running a drip systems. I saw a doc from Nevada that says 1.0 fixture units per sprinkler valve. I see another doc from LA County that says 1.0 per sprinkler head. Need I worry about it with a drip system?

2. If I do go over 39 fixture units, will I need to upgrade my meter to 1" to use 1-1/2" pipe?

3. Should I count my freezer's ice maker? I assumed 1.0 fu for it.

4. I plan to install a loop to recirculate hot water. How do I size the pipe from my last fixture back to the tankless water heater and pump? I assume it depends on the pump flow rate, which I understand needs to be at least .5 gpm to 1 gpm to activate the water heater. I believe a 0.5" copper pipe flows 2.5 gpm, so maybe 3/8"? Maybe this should be a post on its own...

Thank you again. This forum is invaluable!!

Regards,
Aaron
 

Reach4

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1. If you irrigate while you are asleep, and house load is bigger than the irrigation load, then the irrigation would not add much, if any, to the house load.
2. You can drive 1.5 inch pipe with a "3/4 inch" meter. Do you know if you will need a PRV (pressure reducing valve)?
3. Ice maker use is minimal.
4. Hot water recirculation does not consume water, so no need to take that into account.
 

Aaron_808

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1. Ya, I'm not too concerned about it. I can't imagine we will have every fixture in use while we are watering outside... I'm mostly concerned about passing inspection!
2. I have been watching our water pressure. Looks like we have 58-60 psi from the city so we won't need a PRV.
4. I'm not looking at adding fixture units for the water circulation, just wondering what size pipe would be best on the return.

Thanks!
-Aaron
 

Reach4

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4. I'm not looking at adding fixture units for the water circulation, just wondering what size pipe would be best on the return.
Some recirculation systems recirc at a higher rate, but on demand.

1/2 inch is cheaper than 3/8 in pex, but for copper that is probably not the case. Certainly 3/8 ID, and probably even 3/8 OD would be OK for the rate you named. When talking about 3/8 copper, you have to be careful, because there can be an ambiguity.
 
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