Would exposed PEX encourage algae growth?

[Joe B]

My water main shutoff in the garage seemed to have a failing valve that prevented it from closing all the way. Since the valve sat behind the drywall, with the knob protruding out, the plumber not only replaced the valve with a ball valve but also suggested he bring the pipe outside of the drywall.

There are windows in my garage, so there is a lot of indirect, but not bright, light. Will exposed PEX like this encourage algae growth in my pipes?

I will be finishing the drywall repair, but there are exposed segments of semi-translucent PEX that will remain outside the drywall, exposed to light.

Thanks for any insight!

 

[John Gayewski]

Any light exposure WILL cause PEX to fail.

 

[Sponsor]

 

[Breplum]

Cover with any pipe insulation, even the half inch walled stuff, tape the joints and that should do the trick.

 

[Justintime]

The fact it's in an exposed location with PEX voids any warranty from the manufacturer if it fails. It needs to be done right and covered or wrapped. I'm not a huge fan of weird 90 degree angles protruding from walls and whatnot, either. But I guess that's 95% cosmetic on my end.

 

[Fitter30]

Just cover it pipe insulation or a box around it. Could use copper outside the wall to PEX inside with a full port valve.

 

[JohnCT]

Will exposed Pex like this encourage algae growth in my pipes?

I would think any light would, if anything, discourage algae growth. But as others have said, *any* light will have a long term cumulative effect on PEX. Cover it completely.

John

 

[Tuttles Revenge]

Painting PEX with latex paint is a good enough barrier against UV, but doubling that with pipe insulation would be a good redundant method if the paint were to get chipped or if a chunk of insulation were to get knocked off.

 

[Joe B]

The fact it's in an exposed location with PEX voids any warranty from the manufacturer if it fails. It needs to be done right and covered or wrapped. I'm not a huge fan of weird 90 degree angles protruding from walls and whatnot, either. But I guess that's 95% cosmetic on my end.

Thanks - what alternatives to 90 degree angles are there for the goal of bringing the valve outside of the wall?

I was surprised that the plumber chose to use PEX instead of copper for the exposed part.

 

[Joe B]

Thanks everyone! After I patch the drywall I will cover the exposed stuff with well-sealed insulation to keep the light off it.

 

[Tuttles Revenge]

Thanks - what alternatives to 90 degree angles are there for the goal of bringing the valve outside of the wall?

I was surprised that the plumber chose to use pex instead of copper for the exposed part.

There is nothing wrong or unusual about using 90° elbows for what they did to bring the valves outside of the wall. Most plumbers probably aren't thinking about UV rays inside of a building as the effect of UV is going to be much slower, but still is cumulative. We use a lot of propress copper so the transition would have been made that way with copper out of the walls, but covering it is just as effective and likely saved you some money.

There are lots of ways to do the same thing and we're just second guessing theirs.

 

[Joe B]

Thanks Tuttles. Indeed, I have just covered up the exposed PEX with rubber/foam covering.