Cash Acme, based in Alabama, offers SharkBite Push-Fittings that would be ideal for your application. SharkBite fittings can be connected to cPVC, PEX, and Copper in any combination with no tools. It is certified for underground and behind-the-wall applications. You can pressure test immediately with no wait time. Also it is certified up to 200F and 200psi. Here is a link that might be useful: SharkBite Product Info

Update: we pulled the valve apart and the "balancing spool" has rust in it. We're currently setting up a method to re-flush the system (though it was flushed twice during rough in and installation) and Moen is sending us another balancing spool.

Let us consider some of the pro's & Con's of all the code approved materials for potable water distribution. GALVANIZED IRON PIPE: Pro's- 1.proven service life of 60-100 years. 2.Highly resistant to external mechanical shock.(Something hitting the pipe). 3.Not effected by exposure to UV light. CON's- 1.Expensive, 2.Very labor intensive to install. 3.Requires expensive tools to install it, I.E. Pipe wrenches ($25 to $150 each for a quality wrench), pipe cutter($30+) NPT(National Pipe Taper) threading dies (hand die sets $150 to $450+) portable pipe vise($150) or equivalent. Generally these tools can be rented.) 4.Although rare, it can be ruptured by freezing. 5.Has a high suceptabilty to internal pipe wall mineral scaling. BRASS PIPE: Pro's- 1.Perhaps the longest service life of all the options. 2.Highly resistant to external mechanical shock.(Something hitting the pipe). 3.Not effected by exposure to UV light. Con's- 1. Very limited availability, 2.Extemely expensive, 3.Very labor intensive to install. (Requires the same tools as galv. iron pipe). 4.Although rare, it can be ruptured by freezing. Brass and galvanized pipe are very unforgiving mediums to work with and would not be recommended as a DIY project. COPPER PIPE: Pro's: 1.Under most conditions and when properly installed copper has a proven service life of 50 to 75+ years.(AS copper ages it forms a greenish film on the inner wall of the pipe which is coppersulfate, one of the best antibacterial substances known to man thus copper has the highest resistance to the formation of bacterial or microbial growths in the water supply.) 2.Does not form mineral scale on the inner pipe walls. 3.High resistance to mechanical shock. 4.Quick and easy to install with a minimum of tools (tubing cutter, propane torch, emery cloth, flux and lead free solder(total cost for all $50 average). Requires wrought copper fittings and brazed joints when run under a slab within the confines of a structure. Can be brazed with the same torch using MAPP gas. Is considered an easy DIY project for a homeowner or DIY'er with intermediate skills. Is not effected by UV light. CONS: 1.Moderately expensive 2.Under some extemely rare water qualtiy conditions copper pipe may develope pin holes. (In my personal opinion if there is a condition in the water that will eat up your pipes I have to wonder what those conditions do to your body? Would it not be more prudent to invest in a water treatment system instead of shopping for a pipe that might be more tolerant of the problem?) 3.Pipe walls will rupture when frozen. 4.HIgh incidence of theft both of the raw material during construction and from breakins when a home is unattended. PEX: Pro's: 1. Can be economical. Currently the linear foot cost is about 1/3 that of copper however, when run in the modern manifold configuration we use so many more linear feet that often the final cost is more than copper. 2.Expected service life in excess of 75 years. 3.Easy to install, can be fished through walls like electrical cable. 4.Easily bends around corners. 5.PEX tubing will withstand freezing. CON's 1.Not yet code accepted in all places. 2.Requires expensive fittings. 3.Requires the fittings be set with expensive crimping tools. 4.While the tubing will withstand freezing the fittings are made of copper and are subject to the same freezing problems as copper. 5.While it is argued that PEX is the material of choice in areas with acidic water it must be remembered that all PEX fittings are made of the same grade of copper as copper pipe and they are also subject to pinholes. 6.Exposure to UV light(sunlight) deteriates PEX tubing and it must be shielded from direct exposure. 7.For reasons known only to the varmints involved, rabbits, mice, rats and opposums have a high propensity to chew on PEX tubing. 8.Biofilm has the highest rate of growth in PEX tubing when installed in a manifold configuration. (Biofilm is known to cause a number of diseases among which is legionaires disease.) CPVC Pro's: 1.Cheapest of all approved potable water piping materials. 2.Easy to install, requires only a PVC pipe cutter or a hacksaw to cut. 3.Very easy to join. Requires only a means to cut the pipe (hacksaw or hand PVC snap cutter the prime and glue. (The primer and glue must be listed as approved for CPVC under ASTM standard F493). 4.Has no copper components in the distribution system and will tolerate high acidic water conditions. PVC glue is manufactured to ASTM standard D2855 and may not be used on PVC however there are glues available that are listed as approved for both PVC & CPVC-check the labels carefully. Con's 1.Will not tolerate mechanical shock. 2.Becomes brittle with age or exposure to UV light. 3.Maximum working temperature 140degF. 4.Has the lowest resistance to freezing of all pipe materials.

"certainly for any exterior wall applications (in northern climates). Even though it is better to try and use interior walls, that is not always possible with todays open concept floorplan. With pex you no longer have to worry about freezing pipes that crack." WRONG- While it is true that the PEX tubing will tolerate freezing it also must be understood that when a fixture is installed in an outside wall the PEX fixture stubout is also in that outside wall, and if freezing occurs it can and generally will occur first at the fitting. If freezing occurs in the fitting it will expand the fitting wall and the PEX crimp ring so that when the line thaws and everythig returns to normal size the expanded crimp ring no longer has the correct tension and the line is likely to blow off, not to mention that the end use fitting is copper and it is subject to splitting in the same manner as copper pipe. quote "It is nice when you have a manifold in the basement that equalizes pressure." WRONG- a manifold does not equalize pressure. Pressure changes are a result of vertical static head & friction head in the pipe runs. If the lines are sized correctly their is no more pressure losses in a main & branch system then there are in a home run manifold system. Quote;"allows for individual shutoff valves" Per code, all fixtures with the exception of showers and tubs are required to have individual shutoffs and when servicing a faucett on a second floor I find it much more convenient to reach under the sink and turn the angle stop off instead of running down two flights of stairs and locating the manifold to turn the water off. (Perhaps that is why most local codes still require the angle stops even though you have a manifold system). Quote;" It's also much cheaper" When you factor in the cost of the manifolds & end use stub outs plus the amount of tubing required to construct a manifold system in the end the material cost will work out nearly the same if not more expensive. Quote:" and much faster to install" Here again, this is wrong. While it is certainly easier to fish PEX tubing than to run rigid copper to install PEX per complete code, ASTM & manufacturers specifications it reqiires MUCH MORE attention to detail, but then I doubt if one in fifty PEX installations are really up to spec. The bottom line, if you install PEX in a standard main & branch configuration there is a substantial savings in material costs however if you install a PEX manifold system most plumbers will quote the same price as copper. On the other hand, there is nothing that would prevent you from installing a manifold system with copper, in fact, I once worked on a Jail where they did just that. They installed a manifold in a utility closet in the hall way and a separate copper line to every shower, WC & Lav so if a prisoner should happen to tear something off the wall the guards could quickly turn that fixture off without interrupting water service to the other fixtures on the floor.