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Plastic plumbing pipes: this article describes the properties of all types of plastic piping and tubing used in buildings for water supply, drainage, or gas or oil fuels. We include information about failures and problems with some generations of plastic pipes (ABS, polybutylene) and we describe good building practice installation details where plastic piping is being installed. Included is information about ABS, PB, Polybutylene, PEX, PVC polyvinyl chloride and other plastic piping materials.

The articles at this website will answer most questions about plastic building water supply and building drain piping products, failures, and claims as well as many other building plumbing system inspection or defect topics.

Also see PLASTIC PIPE LEAK CAUSES and see PLASTIC & FIBERGLASS TANKS, HDPE and see safety and health advice regarding cisterns and water storage tanks, including plastic water tanks, discussed at WATER TANK SAFETY. Other plastics used in construction that have been subject of failures and/or litigation: see PLASTIC CONTAINERS, TANKS, TYPES and PLASTIC HEATER VENT. Reproduction of this web page electronically at other websites is prohibited.

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Plastic Water Supply & Drain Piping Types, Failures, Inspection, Diagnosis, Repair

As Carson Dunlop Associates point out in the Home Reference Book, as currently used in buildings, plastic water service piping may be polybutylene (PB) - Polybutylene Plumbing Plastic Pipes polyethylene (PE) cross-linked polyethylene (PEX) - Cross-Linked Polyethylene (PEX) Pipe polyvinyl chloride (PVC) - chlorinated polyvinyl chloride (CPVC) - CPVC Chlorinated Polyvinyl Chloride Pipe Plastic building drain piping may typically be ABS -  ABS Plastic Pipes PVC Most plastic piping used outdoors is buried at least 18 inches deep. Exposed piping may be subject to mechanical damage and deterioration from sunlight. Plastic supply piping is popular because it is less expensive and easier to work with than copper. There are many types available including cross-linked polyethylene (PEX), polybutylene (PB), and chlorinated polyvinyl chloride (CPVC). - Home Reference Book, used with permission.

ABS Plastic Pipe Failures, Leaks, Claims, Settlements

PEX TUBING: Cross-Linked Polyethylene (PEX)

PEX and PB plastic pipe are used for water supply in buildings use mechanical fittings (crimp and compression type) and we have found some installers using PEX tubing in low temperature heating applications (see below). PEX piping is also referred to as "cross-linked polyethylene" piping or just "PEX". Our photo (left) illustrates PEX water supply piping being installed in a New York home. Photo courtesy Galow Homes. Installing both building water supply piping and heating supply piping (and radiant heating) can be significantly faster using PEX tubing because of its ability to bend around turns, avoiding some elbows, 45's and other fittings. PEX piping is used in both hot and cold water applications (see the blue and red colors below). By convention the builder uses blue PEX for cold water and red PEX for hot water supply piping lines. Generally you will find PEX piping or tubing marked with the nominal pipe size, wall thickness, and pressure rating and other information (see the illustration just below). Temperature and pressure ratings for PEX, according to Zurn Manufacturing's engineering specifications is 160 PSI at 73°F, 100 PSI at 180°F, and 80 PSI at 200°F.

Illustration of PEX tubing markings - courtesy Zurn Manufacturing (permission requested 12/2010). [Click any image or table to see an enlarged, detailed version.] When installing PEX piping, care must be taken that the pipe does not contact heating ducts. If the pipe freezes, it is less likely to burst than and copper piping. Also, most types of plastic water pipe tend to sag and should be well supported by hangers. Watch out: PEX plastic water piping should not be installed outdoors or exposed to sunlight for long periods. The red and blue PEX piping shown below (right) were delivering hot and cold water in a newly-constructed home. The larger black ABS plastic pipe is probably a drain line. Watch out: do not use plastic piping nor any other type of piping in applications for which it was not intended, or the result could be dangerous. For example, do not use PEX tubing for LP or natural gas piping.

PEX Tubing Connectors: Types, Tools, Requirements

Watch out: a variety of patented PEX tubing push-fit and clamp connecting fittings (at least six types) and connector crimping tools are on the market. You may not obtain a proper and secure PEX connection if you mix tubing connector fittings and crimping tools improperly. We recommend choosing a specific connector type and crimping tool and using it consistently at a given plumbing installation.

Examples & Photographs of the various types of PEX fittings and the special tools used include:

Standards, Listings and Approvals for PEX Plumbing Systems

The following standards and building codes list at least some elements of PEX plumbing systems.

• ANSI/NSF Standard 14 (NSF International)
• ANSI/NSF Standard 61
• ASTM F876 (American Society for Testing & Materials)
• ASTM F877
• ASTM F1807
• CAN/CSA B137.5 (Canadian Standards Association)
• IPC (International Plumbing Code)
• IRC (International Residential Code)
• UPC (Uniform Plumbing and Mechanical Code)
• U.S. State & Local Regulations or Canadian Provincial or Local Regulations

PB Pipe: Polybutylene Plumbing Plastic Pipe Use, Installation Specs, Failures, Leaks, Claims, Settlements

PB or Polybutylene pipe material (photo at left, center horizontal piping) is gray plastic water supply piping that racked, leaked, and its early use resulted in a class action and settlement. By 2010 it would be uncommon to find problematic plastic piping in buildings as we expect that where leaks were a problem, they have in many if not most installations, been discovered and repaired by now.

However home inspectors and home buyers as well as building maintenance staff need to be alert for discovery of older problematic or leaky plastic piping in buildings.

When we see several types (colors) of plastic piping mixed together, especially on older renovation or handyman plumbing jobs we worry that amateur work may have omitted use of the proper pipe glues and sealants.

But the majority of leak problems with polybutylene supply lines involve failure of plastic fittings. Fitting failure may lead to the need for system replacement. This type of fitting was commonly used from the late 1970s until the late 1980s. Copper fittings were used in most installations from the late 1980s until the late 1990s. Failure of copper fittings is rare. Failure of the actual polybutylene piping also seems relatively uncommon.

For at least some of the extensive plastic pipe failure claims, an important factor in the PBS pipe failure mechanism included water that contained significant levels of chlorine. See Chlorine - sources in drinking water for related information.

Connections for PB or polybutylene water piping can be made without soldering, and the pipe is easy to work with, as Carson Dunlop's illustration (left) shows. Our photo (below right) shows hot and cold water piping using these materials and fittings in a new building.

Polybutylene Piping failures:

Polybutylene piping has been (PB) the source of considerable controversy due to failed fittings, especially first generation plastic fittings.- Home Reference Book, used with permission. In this article (below) we include links to information about PB piping failures, claims, and litigation. -DF

PB Pipe: Polybutylene Pipe Failures, Claims, Litigation, Contact Information

Our photograph of a broken white Schedule 40 PVC sewer line in a crawl area (left) illustrates what can happen to this material if a sewer line is blocked and exposed to freezing.

• PB (polybutylene with mechanical fittings) Piping leaks: especially in mobile homes and in the U.S. South, for example trailers and double-wides throughout Florida that were piped with this material - per M Cramer. See "Polybutylene Piping: Time Bomb?" Daniel Friedman, Journal of Light Construction, August 1996 [Technical Q&A].
• Plastic Supply and Drain Piping Failures: leaks, lawsuits, settlements
• If plastic water piping is installed, such as polybutylene water supply piping, it should be at least 18" from the water heater.
• New mobile home and trailer units: 3/4" supply piping, must be installed a minimum of 6" off the ground; a shutoff valve is required. Also see WATER SHUTOFF VALVE LOCATION, USE where to find and how to turn off the main water valve in buildings

• Plumbing Failures: Spencer Class settlement. 10% of replacement cost/damages, only for acetal (plastic)fittings Polybutylene

  plumbing info at U. Arizona Polybutylene piping lawsuit settlement website Polybutylene plumbing lawsuit proposed settlement-old site at http://www.hunt.com/polybutylene/pipe/propset.htm

  Polybutylene Plumbing Failures, Lots of Info about, but slow-loading busy site at http://www.plumbing911.com/poly/index.html

• Polybutylene (Polybutylene) Plumbing (plastic pipes): gray plastic water supply piping cracked, leaked, and resulted in a class action and settlement. www.pbpipe.com

Recommendations (Specifications) for PB Polybutylene Water Pipe Installation

Industry associations, including the Polybutylene Product Line Committee of the Plastic Pipe & Fittings Association have made recommendations for successful installation of polybutylene piping systems, including those listed below. Frankly by 2010 we were never seeing PB installations in buildings at which all of the recommendations below were followed and OPINION it may be that industry experts no longer consider all of the 1990 recommendations necessary. [Feedback invited - CONTACT us.]

• Piping shall comply with ASTM D 3309 (gray piping) Hot and Cold;
• Stored PB piping may be loosely coiled or bundled but should not be taped
• Use annealed copper crimp rings (note this may have changed since 1990)
• Use copper or brass insert fittings
• Compression fittings are permitted if of a type recommended for PB
• Manifold connections (such as for radiant heating) must be of a type recommended for PB
• PB piping should be free of cuts, gouges, or deep scratches, tar, kinks, grease, soldering flux, and should not be faded or discolored
• PB piping end cuts should be square and free of burs (use an approved PB pipe cutting tool)
• PB pipe crimp rings should be 1/8" to 1/4" from the end of the tubing and do not use multiple crimp rings at an individual fitting connection
• PB Crimp rings shall be perpendicular to the centerline of the pipe or tubing (not askew)
• Each PB crimp connection should be checked with a GO-NOGO gauge and any fitting that does not pass should be cut out and replaced.
• In making a run of PB piping allow 1/8" of slack per 12" of run
• The radius of a PB pipe bend should be 12 x the tubing diameter (or more).
• Protective sleeves or bushings should be installed at the beginning and end of straight runs of PB piping when penetrating studs
• Supports for PB piping shall be used at significant changes in direction
• Horizontal support for PB piping should be 32" o.c. for pipes from 3/8" to 3/4" diameter, and at 48" o.c. for pipes from 1" to 1 1/2" in diameter.
• Vertical pipes should be supported at every floor and at the mid-point between floors for pipes smaller than 1" in diameter
• Piping supports should not restrict the horizontal movement of piping
• With PB pipe use only hangers or supports recommended specifically for PB pipes
• Do not connect a hose bib directly to PB piping. Use anchored metal pipe for this transition to avoid strain on the PB pipe
• Transitions should be made with fittings approved for that use
• Keep PB piping at least 6" horizontally and 12" vertically from high heat sources such as heating flues or heating pipes
• Do not use PB piping in recirculating hot water plumbing loops; keep PB piping branch lines at least 36" off of recirculating hot water pipe loops; Hot water heater connections should be at least 18" away from the water heater (and separated by metal piping); do not install PB piping downstream from a demand-type or instant or "tankless" hot water heater.
• Test pressure for PB piping systems should be at least equal to normal system working pressure but also must be not less than 40psi nor more than 225 psi. NOTE that some plastic piping is marked with other maximum pressure ratings that must be respected when testing too.
• Pressure test piping for at least 15 minutes. Note that a light pressure drop in two hours is normal (due to slight expansion of the piping, not due to leaks).

PVC Piping: CPVC Chlorinated Polyvinyl Chloride Water Piping in buildings

Chlorinated polyvinyl chloride (CPVC) pipe is not as flexible as PB or PEX and the fittings are solvent welded (glued) rather than press-on. This pipe is likely to split if freezing occurs. CPVC pipe is suitable for use on both hot and cold water lines. - Home Reference Book, used with permission.

Our photo (left) illustrates Royal brand PVC sewer piping being installed at a New York Home. Photo courtesy Galow Homes.

Watch out: PVC polyvinyl chloride pipe produced by JM Eagle Corp. is reported to be defective, leaking or breaking as early as in the first year after installation. Details are at PLASTIC PIPE LEAK CAUSES.

Watch out: Using the wrong solvent adhesive, or not using it properly (including pre-cleaning the pipe joints) not only results in leaky plumbing, also the purple solvent cement makes permanent stains, as Oatey Plumbing points out:

The pigments or dyes in Oatey Purple Primer and Oatey Purple Primer/Cleaner are permanent. Depending on the type of material stained, its porosity and the length of time the stain has set, it may be possible to remove or lighten the stain. We recommend blotting a clean, dry towel with Oatey Clear Cleaner to attempt to remove the stain. It may not be possible to remove the colorant from particular fabrics or surfaces. The finish and/or color of certain fabrics or materials may be dulled or discolored when in contact with solvents in Oatey Clear Cleaner. You may want to try the cleaner on an inconspicuous spot before using on the stained area. Please use our purple primers and colored cements with caution.

PVC is Poly(Vinyl) Chloride, CPVC is Chlorinated Poly(Vinyl) Chloride and ABS is Acrylonitrile-Butadiene-Styrene. PVC and ABS pipe are normally used for drain, waste and vent (DWV) systems. CPVC is used for water distribution systems. It is important to choose the correct solvent cement or pipe glue based on the type of plastic pipe being used. Our photo (left) shows a close-up of markings on PVC sewer piping. Note that we took this picture of pipes resting on a gravel driveway. You should not bury plastic sewer piping in sharp rocks but rather it should be bedded in sand and located 18" below the ground surface or deeper to reduce chances of damage from rocks or from vehicles passing overhead. Photo courtesy Galow Homes.

General Comments about Plastic vs Copper Piping in buildings

Many plumbers prefer to work with copper and, although plastic pipe is less expensive than copper, the fittings are expensive. Some areas do not allow plastic pipes based on environmental concerns. Some questions have been raised about the chemicals used in the adhesives used to join sections of piping, and the toxic gases given off from plastic piping during a fire.

Polyethylene (PE) and polyvinyl chloride (PVC) are only suitable for waste, underground water service pipes or cold water piping systems.

Our photographs of plastic water supply piping connections show a new water main (below left) and building supply pipe being connected to copper piping entering a building (below right) in San Miguel de Allende, Guanajuato, Mexico in 2010.

- Adapted with permission from The Home Reference Book

Questions & Answers about plastic pipes used in buildings for water supply, drainage, gas, etc.

Question: Do Rodents Attack Plastic Tubing or Piping? Does the tubing color make a difference in rodent resistance?

This might seem a strange question but we have blue plastic used for the connection from our gas tanks to our cooker. We have just had it serviced and have been advised that it should be yellow plastic. We have had the blue plastic for a lot of years and have been told it must be changed because the yellow tubing is not susceptible to vermin. Since we have never had a problem with vermin and the blue tubing – I was wondering how true this is and why do the vermin not like the yellow tubing. It would be good to get some advice before we start doing unnecessary work. Thank you for your help - D.M.

Reply: Yes, No, and maybe

We have indeed had reports of rodents chewing on plastic piping of various types, colors, brands, and application (water piping and gas piping for example).

You didn't say exactly what kind of plastic piping you are using nor its brand - that information would let us check with the manufacturer for recommendations about rodent proofing the piping. Certainly we don't want a rodent-chewed hole in any piping but in gas piping it would be particularly dangerous.

I am doubtful that changing from one color piping to another would make much difference in rodent resistance if the piping brand and material is the same; but if the color change includes a change of material, the new material might be more rodent resistance. In a New York installation I have seen yellow plastic-covered flexible copper tubing used for both gas piping (not through walls and ceilings or hidden locations) and heating oil piping. A mouse that chewed the outer plastic cover would most likely not get through the copper, but you'd lose the protective coating at that spot. At that same installation, we used threaded black pipe for gas piping where it runs through hidden locations such as ceilings and walls.

If your pipe damage is occurring indoors you need the services of a pest control expert - an "exterminator" too.

If you can send along details about the pipe type and brand we'll research further. See the CONTACT link on our pages.

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  PLASTIC PIPING
    ABS Plastic Pipes
    Polybutylene Plumbing Plastic Pipes
    Cross-Linked Polyethylene (PEX) Pipe
    Polybutylene (PB) Pipes
    CPVC Chlorinated Polyvinyl Chloride Pipe
    PB Polybutylene Pipe Failure Claims
  PLASTIC PIPE LEAK CAUSES