Protecting a water main from Pygmy Date Palm roots

[Tom in Havasu]

Hi All,

I need some advice. I have a water main that just broke under a 100 ft long driveway going up a hill. We will dig a 12 inch wide trench where the concrete driveway will broken out 100' long all the way up the driveway next to a wall.  My thought was leaving the trench open then planting 5-7 Pygmy Date Palms going up the driveway every 10 or 20 feet, palms would start out at 3ft tall, then covering the dirt/open trench with 1" decorative rock.  However my plumber says the roots could damage the main line planted below, which will be 12" deep. The Pex main line will be encased by 1.5" PVC pipe for protection. 

One of my thoughts for additional protection was to encase the PVC and main line with concrete about three feet on each side of the planted root ball.  Or I could take 5' sections of 2" steel pipe, or ABS pipe and encase the new water main.  Any thoughts and experience would be appreciated.

[Merlyn]

@Tom in Havasu generally palm roots are not considered "invasive" and won't rip up concrete or destroy pipes, etc.  However...that's probably a lot of money being spent to put in a 100' long new line, so protecting it with something is a good idea.  I don't know if PEX is resistant to roots, my gut feel is that it's not. 

• PVC around the PEX is probably tough enough for Pygmy Date roots, especially if there's no water source for them to want to invade.  It would be easy to pull new PEX through in the future in the case of a failure.
• Galvanized 2" steel pipe might be overkill, but would probably last 100+ years and also be fairly easy to pull replacement PEX.
• Concrete around PVC around PEX is probably also overkill.  I'd guess it's the most expensive, unless they are already pouring new concrete anyway.  In that case it might be the cheapest and would certainly work. 

The galvanized steel is probably the only option resistant to dicot roots like oaks, so if that's a concern that's the way I would go.  But in reality any of those options around PEX is probably super tough and future-proof for pulling replacement PEX.

[Harry’s Palms]

The only problem I had with palm roots invading pipes was on a French drain on the side of my house. The original pipe was thin wall and not glued. I had it replaced with a heavy duty pipe with glued connections . I cut so many roots when they came to dig the trench I thought the palms would suffer . Not one brown frond! They didn’t even know what happened. That was years ago and the pipe is still clear , no roots. Harry

[miamicuse]

I think there are many ways to look at it.

You are concerned about roots invading the pipe like penetrating into the pipe?

However, I would also be concerned about the opposite.  What if you need to make a modification to your water line later on, how easy is it to do it?  Just for the sake of argument, let's say you want to insert a tee fitting to branch off for irrigation or to a shed or to a detached workshop.

- will these palms be in the way of you getting access to the pipe?  They may not penetrate the pipe but they may be above, below, around the pipe, you still need to cut them out of the way to access.

- what if you have a leak?  Instead of using a moisture meter or look for a damp spot in the ground, you put PVC, steel and concrete around this pipe, now the leak location cannot be determined except water jets out both ends and you had to disconnect and pull the whole tubing out to make repairs.

any reason you opt to use PEX tubing?  If you are going to use PVC as a sleeve may be consider PVC as a main until you reach the house, or poly.

[SeanK]

Buy a 100 foot roll of copper and sweat each end. Much easier.

[Tom in Havasu]

12 hours ago, miamicuse said:

I think there are many ways to look at it.

You are concerned about roots invading the pipe like penetrating into the pipe?

However, I would also be concerned about the opposite.  What if you need to make a modification to your water line later on, how easy is it to do it?  Just for the sake of argument, let's say you want to insert a tee fitting to branch off for irrigation or to a shed or to a detached workshop.

- will these palms be in the way of you getting access to the pipe?  They may not penetrate the pipe but they may be above, below, around the pipe, you still need to cut them out of the way to access.

- what if you have a leak?  Instead of using a moisture meter or look for a damp spot in the ground, you put PVC, steel and concrete around this pipe, now the leak location cannot be determined except water jets out both ends and you had to disconnect and pull the whole tubing out to make repairs.

any reason you opt to use PEX tubing?  If you are going to use PVC as a sleeve may be consider PVC as a main until you reach the house, or poly.

Good points! Thank you.

We are going to add a large RV garage and casita above the garage on another part of the property, but will have access to the water main for that down at the bottom of the hill where the water meter is.  Also at the top of the hill is my attached garage, I can access the main line there before it goes into the house for any other irrigation needs, etc. The current water line is 3/4" and has a pressure safety valve to reduce the city pressure down from 95psi to 50psi at the house. We are future proofing by going to a 1" main and should have plenty of excess volume since we have massive pressure from the city. 

The main reason we're looking at pex is the water coming from the city has a high akaline content which is very hard on copper and many homes including mine have been flooded after having pin holes and corrosion. So the choice is Pex or PVC, from what I've read Pex is a better choice, less chemicals coming into the drinking water.  I'd much rather go cooper. 

One of the benefits of leaving the trench open with the palms and decorative rock and not covering back up with concrete is we will be able to dig it up and make repairs.  Could we have a problem with roots, yes, I'm just trying to figure out how to minimize that.

[Tom in Havasu]

Unfortunately copper corrodes with the city water in our area, too much alkalinity in the water and homes flood often that have copper.

[miamicuse]

I understand your concerns about copper pipes.  Pin holes can develop from a number of issues too low or too high PHs, calcium deposits, abrupt size changes causing excessive turbulence or scouring, copper wall too thin like type M etc...

No piping material is perfect unfortunately they all have issues.

PVC is easy to install, but can easily shatter from the hit of a shovel, and does not do well with UV or exposed installation.

PEX is also easy to install, can minimize joints, and there are many options PEX A vs B vs C, and fittings come in many many variations from cold expansion to clamps to cinch to push-in and each of these have their pros and cons.  I do question PEX's suitability for exterior underground application as a "main feed".  Another consideration is PEX tubing in general has quite a bit of class action lawsuits (Uponor, Wisbro, Nibco, Zurn all have them) so much so that PEX (specifically those installed prior to 2011-2012) is beginning to appear on home owner insurance prohibitive list like polybutylene pipes, K&T wiring, asbestos roofs etc... as an item, if present, that they will either increase premium substantially, exclude or deny coverage altogether.

In the state of Florida we are also seeing some plastic pipes being eaten by subterranean termites.  One material that keeps getting damaged is soft PVC used a lot in pool and spa piping, not sure if this is an issue in your area.  We also suffer from rodent damages occasionally.

One alternative worth looking into is HDPE.  This is used by many municipality for their feeds and is more heavy duty than PEX.