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New Member

Posts: 3

Location: USA


Friday, April 2nd 2004, 7:53am

Installing a drip irrigation system

After spending entirely too much time the last couple years manually watering the landscaping around the house, I've decided to install some sort of drip irrigation system this year. What I envision is three to four zones using poly tubing at ground level covered with mulch.

<b>Q1</b>: What is the typical lifespan of, say, 1/2" poly tubing (let's say Rainbird 700 series or Toro blue stripe) if it's covered with mulch?

My original plan was to have an irrigation company install the backflow preventer while I do the rest so I fielded quotes from a few local companies. All agreed that a dedicated hose spigot was the best way to supply the water (as opposed to teeing at the meter).

They varied wildly on the backflow preventer, however. The first company wanted to attach a RPZ to the spigot. One suggested a PVB and two installers said a simple $4 hose bib vacuum breaker would be sufficient for a drip system. Keep in mind that local plumbing codes require at least a PVB for all underground sprinkler systems.

<b>Q2</b>: Would a surface drip system not fall under the same requirements? Would a hose bib breaker indeed be sufficient? Somehow I think not. Does poly tubing expand and contract with water flow? If so, could that cause back pressure which would defeat a PVB? (okay, okay, I know there's more than one question under this heading)

<b>Q3</b>: Are there any problems associated with attaching a PVB to a spigot?

<b>Q4</b>: Is an underground valve box still the recommended way to do this even though the water source will be an above ground spigot and all distribution lines will be on the surface? Would some sort of above ground valve box be a definite no-no?

<b>Q5</b>: I live in hardiness zone 6 so the system definitely needs to be winterized. Are there any special precautions to take when winterizing a drip system? Should the PVB/RPZ be left in place or is it standard practice to remove them and take them indoors for the winter?

Thanks in advance.


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