As I mentioned in my answer to your question in the other forum you posted it in, I think going to a plumbing shop would be your best bet as to what to use for your project. In this forum, you might want to find one of "roboladys" posts and go into her website as she has extensive projects to look at.

mksmth is correct. In fact, the grey PVC conduit I buy here has painted on the side that it is treated for UV resistance. I've gone to it exclusively for my garden projects (too bad I didn't know this when I built my PVC greenhouse.....).

Glueing PVC pipe is not really a glueing process, it is a chemical welding process whereby both materials are softened by the glue and melted together in the same manner as a thermal weld would attach metal. The primer removes the glazed surface of the PVC in the area of the chemical weld to allow the PVC glue to penetrate into the pipe & fitting wall to insure the correct penetration. Failure to use primer results in substandard faulty welds that may or may not withstand the pressure and vibrations of normal use.

QUESTION: If PVC pipe is no longer approved for plumbing water distribution piping within a structure why do they carry such a wide variety of PVC pipe & fittings in the local hardware or home supply store? ANSWER: First of all, it must be understood that the retailer must keep an inventory to meet the demand of their entire customer base whereas, both residential and commercial plumbing only represent a small percentage of the total overall customer base of the hardware retailer, by example, 1. Landscaping Contractor generally select PVC as the material of choice for landscape irrigation systems. 2. Swimming Pool contractors use PVC as the material of choice for installing pool-filtering equipment. 3. HVAC contractors use PVC for AC condensate drains, Combustion air intakes and on direct vent furnaces they use it for the exhaust flue. 4. Electricians use PVC for electrical conduits. 5. Farmers use PVC for conveying liquid fertilizers, running temporary water lines to remote stock watering tanks or conveying liquefied manure. 6. PVC has thousands of uses in the industrial environment such as conveying lubricants, process water or brine solutions and in some instances raw materials related to the production at hand. 7. In the Food Processing Industry they use a tremendous amount of PVC for conveying both liquid and dry ingredients from bulk storage to the processing vats or from the vats to the canning or bottling process. In fact, the food processing industry is the prime consumer of clear PVC pipe. As you can see, the hardware dealer has no way of knowing what end use application the customer is intending for the products they sell. It is the sole responsibility of the installer to know what products they may or may not use, in fact even though code now prohibits installing PVC in the house potable water distribution system, under certain conditions a Plumber or Maintenance man/woman may be required by code to install PVC in your house when performing "maintenance" on your potable water distribution system. Does that seem a bit confusing to anyone? Allow me to explain: In most jurisdictions the codes state that a homeowner or his/her delegated maintenance man/woman may perform "Maintenance" without pulling a permit. In addition, a homeowner may pull a self-help permit to perform "Plumbing" providing the plumbing is to be installed in a single family dwelling, which is used exclusively as the principal domicile of the homeowner & his/her immediate family. It is further understood that when a homeowner pulls a self-help permit he/she will be required an inspection and they will be held totally responsible for full code compliance of all work performed. As you can see, the question then becomes, what is "Maintenance" and what is "Plumbing"? It is assumed by the code that the initial installation was inspected during the installation process and it met all applicable codes in force at the time of the installation By legal definition "Maintenance is the act of maintaining an existing system in its original configuration including all pipe, valves, fixtures and appurtenances" and thereby it is grand-fathered by the original installation code, permit & inspection. As an example, let us assume for the moment that you bought a house, which was constructed in the late 60s or early 70Âs when PVC was approved for potable water distribution and your entire layout is PVC. In this case, by legal definition if one of those PVC lines were to fail you may replace it with PVC as an act of Maintenance and not violate any code or require any permits or inspections. On the other hand, if you were to remove the defective PVC line and replace it with Galvanized Iron Pipe, Copper, CPVC, or PEX that would legally be defined as an act of Plumbing because you are altering the original design in which case you would be required to pull a permit and all valves, piping, fixtures and appurtenances downstream from the point of transition from the original PVC pipe would be required to be upgraded to current code approved materials and all work would be required to be inspected prior to use. As you can see, while the codes prohibit PVC for new construction, if the original distribution system was installed with PVC we are required to use PVC to repair it.