Help! What purpose does this water line serve? Pic included.

dahlia55 wrote:
We were also wondering if that is PEX or PVC. Assuming it is PVC as the line is marked, "180*F / 100 PSI"

As other have said that clear reinforced vinyl line is for your bypass now a little info on line colors:

1. That Grey line is most likely Poly-Butyl which was used from the 1970s till 90s and was basically outlawed because it would get brittle and leak due to the chlorine and especially in hot water. I personally would replace it or be very, very cautious and NEVER leave you water lines pressurized even on city water if you are not physically in the trailer. It is a disaster just waiting to happen and it is also prone to cracking and leaking especially at fittings just from the movement in TTs.

2. PVC is not rated for hot, only cold water and is usually white in color.

3. Before PEX which can be any color, but is easily identified by the metal bands used in the fittings. You could run into PEX with Shark Bite or Quest fittings, but they would not come from the factory with those. The alternative was CVPC which is generally cream in color and is rated for both hot and cold water. CVPC is sort of out of vogue and harder to find with PEX being the most common water line used today.

Before someone finds what can surely be exceptions to the colors I mentioned above what I posted is what I consider a very good first cut on identifying the type of lines.

Larry