Let’s start off with the home improvement plumbing fresh water system. You need to have a waterline coming from a well or a city water supply.Most mainlines will be made of 1-inch pipe, but some codes allow ¾ inch.
The main water shut-off needs to be installed somewhere easy to get at. It needs to be between the main waterline and the water heater.
From there a ¾ inch pipe goes to a branch where one line is feeding into the water heater, the other line will service all the cold lines in the house.
There will be a line coming out of the water heater that will run along side of the cold line to all the fixtures.
The picture above shows how the cold and hot lines are routed to the different fixtures. When copper or galvanized pipes are used, this is usually the way it is run. Most often, ½ inch pipe is used.
There is also another way to do this, which is becoming more and more popular among home improvement plumbing projects. About 20 years ago, plastic tubing called polybutelyne or PB tubing was being introduced into new residential construction.
The idea was great, but the plastic wall in the tubing was too thin and there were several mishaps after a few years of use and PB went away. Since then, a few new plastic products have been introduced, but there are a few states that still remember the PB incidents and won’t allow the use of poly tubing.The kind of tubing mostly used is Quest or also called Pex. It is a stiffer and thicker plastic material than the older PB. It is a dream to work with because of the flexibility and it’s much cheaper than copper and galvanized pipe. It’s perfect for plumbing projects.
With Quest, everything is run directly off a manifold. Each fixture in the house will have a separate line feeding it. The manifold acts like a hub and is located near the water heater. It is basically a box with two sections, one section for cold water, and one for hot water.
A fresh waterline goes into the bottom and feeds all the cold-water fixtures. It also has a cold line running to the water heater. The water heater then has a line for hot water that runs back to the manifold and feeds the hot-water fixtures.
Each fixture has its own dedicated waterline. The red (hot) or blue (cold) tubing usually runs side by side from the manifold to each fixture. The flexibility of the tubing makes it a dream to work with. Even beginning home improvement plumbing amateurs can use this stuff. In the picture above we see the different sizes of tubing. The water manifold above shows how a typical Pex fresh water system is installed.
Pex tubing has many different fittings made of either brass or poly. These fittings slide into the tubing and are crimped in place with crimp rings and a crimper.
In my opinion, Pex is a good alternative to expensive copper or galvanized pipe. It is very inexpensive and is so easy to work with for home improvement plumbing projects. The one thing however; that is uncertain about Pex, is the long-term effect of chlorinated water on the vinyl walls in the tubing.
There is little reason to suppose that a chemical reaction between chlorine and the vinyl, could cause the tubing to weaken over time, but nobody really knows for sure yet. The new product does seem to be very dependable. It outperforms metal pipes in extreme cold conditions because of its resiliency.
Copper and galvanized pipes freeze and break if they are left unprotected in the cold. Pex can usually freeze and thaw several times before it breaks.
Don’t confuse Pex with CPVC. CPVC is a type of stiff vinyl that is used mostly in mobile homes. It is a poor product in cold weather. It shatters easily and is not that easy to work with. I don’t like it because I have had to replace it with Pex many times in campers and trailers that weren’t properly winterized.
Plastic tubing is a much simpler approach to fresh water systems than copper or galvanized, but before you make any plans, you need to first find out if it is legal to use. There are a few areas where no form of plastic pipes is allowed, not even ABS for waste lines. Installing cast iron pipes is a whole lot of no fun and it’s spendy, but sometimes there aren’t any other options.
When you use plastic tubing for fresh water, each line is dedicated to its own fixture so you don’t need to put a tee in the line anywhere. That way the pressure remains constant. About the only place where a tee is acceptable is for a refrigerator waterline that runs the icemaker and water through the door.
It isn’t really even a tee though. Refrigerator lines are just a small flexible tube that attaches by means of a puncture seal that you twist until it forces a hole in the poly or copper waterline and makes a tight union.
So basically, you attach one end of the Pex tubing onto the manifold using a female hose fitting, run the line to the fixture, and then attach it to the fixture using another female hose fitting. You can secure the tubing to the floor joists and wall studs with plastic holders made exclusively for Pex or Poly.
Don’t use metal fasteners that are normally used for copper or galvanized, because they could wear a hole in the tubing over time. Flexible plastic lines are light and they vibrate more than metal lines do. Pex comes in a few different sizes. The water mainline coming into the manifold will probably be a 1-inch line of strong poly. You will want to have a main water shut-off valve before the manifold. You will need to plan this part of your home-improvement-plumbing project with the help of the inspector.
The cold waterline from the top of the manifold that goes to the water heater will probably be a ¾ inch Pex line as well as the hot waterline coming from the water heater back to the manifold. You can use 3/8-inch thick pex for the individual fixture waterlines if you want, but ½ inch delivers a larger volume of water and is preferable.
Copper and galvanized lines are run in a straight line usually both hot and cold side by side with tees or branches servicing each fixture. They are a little bit trickier to run though. I strongly recommend using Pex for new home improvement plumbing projects.