SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

The correct way to pipe the system is to use 1-1/4" copper right off the outlet of the meter or as close to the meter outlet as possible. Use 1-1/4" copper line until you get to your poly pipe for the main lines. Use 1-1/4" poly pipe for all the main lines and 1" for the lateral lines (lines that come off the main line to feed a couple of heads). This will conserve pressure.

If cost is an issue, use 1" poly pipe everywhere, however, I would make sure none of the zones used over 10 gpm since you will be lossing too much pressure if you exceed 10 gpm.

Definitely use the 1" PVB. Since 1-1/4" PVB's have the exact pressure loss through them as the 1" and the 1" are much cheaper. Only difference between a 1" and 1-1/4" PVB is the thread size in and out of the unit.

Do not use a filter for the whole system if you are using city water. You will only need a filter for the drip zones since the pore sizes on the drip emitters are so small. To filter the drip zones use the Xerigation Control Zone kits from Rain Bird which include everything you need for a drip zone (valve, filter, pressure regulator, and an isolation valve to allow easy cleaning of the filter). Here is the link for the Xerigation Control Zone Kits.

I suggest using the Hunter HPV valves if you can afford to since they are readily available and are the highest quality valve available. The last thing you want to be doing is replacing one of the valves in the next couple of years. HPV is the best valve to withstand temperature swings and the diaphrams are long lasting. It is a valve with every feature you could ask for to attain long-lasting, heavy-duty performance. Rigid internal support to prevent stress failure in high pressure situations. A unique porting system with a superior ability to filter dirty water that also closes slowly to suppress water hammer. Low-flow capability for effective drip applications.

If you can not afford the HPV then I suggest the Hunter PGV valves which are very good valves. They feature durable high-grade construction and a rugged diaphragm with a support to prevent stress failure.

I suggest the Hunter I-20 rotor over the PGP if you want the best, longest lasting rotor avaiable. The I-20 is built more heavy-duty!
However, you can't go wrong with the PGP either since it is the standard in the industry.
The I-20 has the following which the PGP does not:
- an Extra-strong spring for reliable retraction every time
- a drain check valve for up to 10 feet elevation change, saves water, reduces liability
- FloStop® Control allows stoppage of flow through an individual head while remainder of system is running
- Comes with a standard set of nozzles, however you can order short radius nozzle sets and use the I-20 rotor for all areas needing covered from 17 ft to 47 ft.
Here is the link for the I-20 Short Radius Nozzle sets.


Rain Bird 1804 pop-up spray heads are the best to use. I agree with your choice.


Technical Data:

Water meter can supply a maximum of 18 to 20 gpm

1-1/4" copper: pressure loss @ 13 gpm is 2.21 psi/100ft (velocity: 3.68 ft/sec)
1" copper: pressure loss @ 13 gpm is 6.57 psi/100ft (velocity: 5.76 ft/sec)TOO Much Velocity 5ft/sec is the usual limit!

1-1/4" poly: pressure loss @ 13 gpm is 1.34 psi/100ft (velocity: 2.99 ft/sec)
1" copper: pressure loss @ 13 gpm is 5.08 psi/100ft (velocity: 5.19 ft/sec)TOO Much Velocity 5ft/sec is the usual limit!