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What To Do



Tuesday, April 14th 2009, 8:34am

Drip System

I plan on having one circuit of drip system that will cover an area in
my front yard and an area in my back yard. This will originate from
one valve. Which is better to do in this scenario, to get a drip
regulator kit and replace the valve on the manifold or to get area
pressure regulators and regulate the pressure at the end points of
water distribution? I pretty much think the latter is the answer but
what components should I use for distribution? I plan on running 1"
Poly to these locals with 1/2" riser fittings or whatever is suggested
to use to tee off from these 1" pipe fittings.

Questions about
the Valve Box and backflow preventer: I have a 1" PEX line running
from my basement to the side of my house where my valve box will be
logically located.

1: Can I install my double check valve inside the house in the basement to free up space for the valves.

Is it ok to use keystone clamps on PEX pipe or should I use PVC on the
outside of the home as I have read that PEX should be buried at all

3: If it is ok to use PEX outside, is it ok to use PEX
clamps on a poly fitting? You see where I'm going here, I was thinking
of just using a 90 degree poly fitting to connect the PEX to a 1" poly
line and then down to the manifold in the valve box. How should this
normally be handled?

4: What other fittings should I put on
the outgoing line to blow out the lines for winterization? Should I
put a shut off valve downstream of the double check valve and then a
tap for blowing out the line downstream of that? Can it all be
achieved in the basement so I don't have to clutter the valve box?


Supreme Member


Tuesday, April 14th 2009, 9:41am

I can't answer any of your questions on PEX. I don't have any experience with them. All the work I've done around my house has been with copper and PVC.

First, for backflow preventor, I assume when you are talking about a double check valve, you really mean a double check valve backflow preventer. Logically, they are SORT of the same thing, except the backflow preventor will have the needed test cocks that can be used to prove each check valve is properly working independantly of the other. Simply putting in a double check valve is NOT considered proper backflow prevension.

Second, are double check backflow preventers legal where you live for irrigation backflow prevention. Local codes vary greatly on this issue, with some being so strict that allowed backflow preventers are specified by part numbers and required a certified plumber to install them... to some simply saying something along the lines of "adiquate backflow prevension is required".

If a double check backflow preventor is legal where you live, and you never plan to inject anything into the irrigation lines (such a fertigation equipment to fertilize as you irrigate) then YES, a double check backflow preventor can be installed in the basement, or just about any where in any orientation. Unless specified otherwise by local codes, the only limitation is that you must have it installed such that the test cocks are properly accessable for testing the device.

Given that you are talking about 1" pipes running underground from the manifold to the planting beds (at which time you are transitioning to 1/2" drip tubing for above ground), the flow rates should be relatively so low that you shouldn't have to worry about pressure losses through the 1" pipe and therefore you can just install a single pressure regulator at the valve.

One of the things you seem to have left out is a filter. Because of the tiny pores associated with drip equipment, drip irrigation REQUIRES that the wate be filtered with a very fine mesh filter. If you get a drip zone assymbly (something like one of these:, the filter will come with the valve and regulator.

Otherwise, the only other thing I can mention is you have to make sure you are following codes for pipe going from the point that you tie into your water main to the point of the irrigation valves. That pipe will be under constant pressure and therefore you have to make sure the pipe is suitable for that. In my case with copper and PVC, PVC is ONLY rated for main line water pipes when they are buried 18" underground (mainline in this context means pipes under constant pressure, while the pipes AFTER the irrigation valves are lateral lines and are only pressurized when the zone is on and therefore do not have to follow the same standards as mainline pipes). So for me, I would have to tie into my copper mainline in the basement, use copper to the backflow preventer, and then copper out of the basement.

However, I instead tied into my mainline out at the street where is was a 1" burried PVC.

If you install a connection point to blow out the system for winterization, such a connection must be AFTER the backflow preventor, and you should install a shutoff between the backflow and the blowout port. (The backflow preventer likely has a shutoff and the end of it that could be used to block pressurize air from heading back toward the backflow during blowouts... but since you are just installing stuff, adding an additional shutoff allows you to isolate the backflow preventor should repairs ever be needed on it. And of course you need another shutoff between your mainline and the backflow preventor.


Starting Member


Tuesday, April 14th 2009, 8:59pm


Thanks for the information, I'll pick up a drip valve assembly kit for one of my 4 valve positions, install the backflow preventer, after-bfp shutoff valve, and blow-out valve in the basement, and probably use PVC for the pipe from the 1" PEX line coming from the side of my house to the in ground valve manifold. :D

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