Pipe Water Line Types

Several types of material has been used in the past for pipes - brass, copper, CPVC, galvanized, lead, polybutylene, cast iron, and even wood for example. Consumers today have many choices when it comes to selecting products to use for home plumbing. Although products such as lead service lines are no longer used due to health concerns, copper, CPVC, PVC, and PEX are just a few of the options available today for residential plumbing uses.

Copper

This is the best and most commonly used type of pipe today. The use of solder and compression fittings is necessary for joining and working with copper pipe.

If the water PH level is below 6.5, there is the potential for copper to leach from the pipe into drinking water above allowable levels.

Copper is considered by many plumbers to be the easiest type of pipe or supply line to add on to and repair. Keep in mind that when installing copper pipe, leave adiquate room for future service work. Since the application of heat is necessary when working with lead soldered copper pipe fittings, space is necessary to enter the service area.

PVC and CPVC Plastic

Modern plastic plumbing products are usually designated with either "NSF-PW" or "NSF-61" to indicate that the product complies with the health effects requirements of NSF/ANSI Standard 61 for materials designed for contact with water.

CPVC

CPVC plastic piping has a very high expansion / contraction coefficient. This piping grows significantly when hot water flows through it. The growth can be nearly 5 inches for every 100 feet of piping if the temperature of the water rises 100 F. Water temperature in regular household piping rarely rises 100 F, but even if the temperature goes up just 50 F, the pipes can expand causing all sorts of noise. If you decide to use CPVC, make sure the pipes are not tightly clamped and they pass through large enough holes in wood framing members so they do not bind.

PVC

Regular PVC plastic pipe is typically restricted for cold water use only. PVC should never be used for hot water. In some areas plumbing code requires that the same pipe type be used for hot and cold so in that case PVC could not be used at all.

Polybutylene Plastic

This type of plastic pipe is gray and very pliable, but unlike CPVC, "polybute" is very rugged. In freezing temperatures it will expand to reduce the risk of splitting. In the first days of polybute there were faulty fittings. It is easy to snake polybute pipe through walls without the need for concealing joints.

Several 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.

PEX

Cross-linked polyethylene, commonly abbreviated PEX or XLPE, is a form of polyethylene with cross-links. PEX pipe is suitable for use with hot or cold water. PEX is manufactured and tested according to stringent national consensus standards: ASTM F 876, F 877, AWWA C904 and CSA B137.5. PEX is included in all of the major model plumbing codes used in the United States and Canada; NPC, UPC, IPC and NSPC, and approved by HUD for hot and cold potable water plumbing use.

With the proper adapters, PEX pipe can be used with steel, copper, PVC and CPVC plumbing pipe. PEX is the most flexible plumbing pipe available. It can be bent around most corners without a coupling or fitting. For example, 3/8" pipe may be bent to a 4" radius and 1/2" pipe to a 5" radius. PEX flexibility also allows it to expand and contract more than other types of pipe.

PEX 's flexibility and strength at temperatures ranging from below freezing up to 200 degrees Fahrenheit makes it an ideal piping material for hot and cold water plumbing systems, service lines, hydronic radiant heating systems, snow melting applications, ice rinks and refrigeration warehouses.

Flexible systems are quieter than rigid piping. The smooth interior will not corrode which can affect other materials long term pipe flow characteristics. PEX is also very freeze- break resistant. PEX systems have fewer joints and are easier to install providing a lower cost installation over traditional plumbing materials.

PEX is designed and tested to perform as well or better than any other material approved for hot and cold-water distribution systems. For indoor plumbing applications, PEX is expected to perform as long as copper, CPVC or any other approved plumbing distribution materials.

The PEX Supply Water Piping page contains additional information.

Galvanized Pipe

Many older homes still have old galvanized iron water supply lines. Eventually they clog with deposits and water pressure and volume drop. Installing new copper tubing or CPVC tubing is one solution.

Galvanized metal is still used for some residential purposes, such as well casings, although it is not frequently used inside the home today. Rust buildup can occur inside of small-diameter galvanized pipe over time, causing the water flow to become restricted. In some situations, the water coming from the faucet can appear rust-colored when it first comes out each time the tap is turned on.

As galvanized iron water lines age the interior of the pipe gets clogged with mineral deposits. Hot water temperatures seem to accelerate the growth of these deposits. The mineral buildup does not affect the water quality, but it indeed has an impact on the quantity of water the pipes can deliver.

Galvanized iron water lines are easily identified. The outer diameter of the pipe is often 7/8 inch. The pipe is gray in color if it has never been painted. Where a pipe enters a fitting, you will see threads on the end of the pipe as you might on a standard threaded screw or bolt.

Worn threads on galvanized fittings are a frequent cause of leaks. When working around old galvanized fittings, any significant jarring or vibration can cause to let go and cause a leak or burst.

Lead

Lead pipes were used many years ago to connect our homes to the water main in the street. As we now know the potential health risks associated with excessive lead levels in water, lead pipe is no longer used and has given way to alternative like copper. Lead in drinking water can result in brain damage and other health problems.

To determine if your home has a lead service line, locate the place in your home where the water line comes through the wall or floor in your home. Is the pipe a light gray in color? If so, while wearing gloves to protect your hands, carefully take a penknife and lightly scrape the outside of the pipe. If the pipe material is soft to the touch, you may have a lead service line.

Have a lead test performed on your water to ensure that the lead level is below 15 ppb (0.015 mg/L). You can use a home water treatment product certified for lead reduction, or use bottled water for drinking and cooking. Keep in mind that faucets or lead-based solder (used to join copper tubing) that was manufactured before 1998 may contain a higher amount of lead than permitted in today's products, so these materials can also contribute lead into drinking water. Due to this, lead can be present in a home water system even if there are no lead pipes.