How To Look At A House

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What are the most common plumbing problems with older houses?

Sunday, July 29, 2018

There are three categories of plumbing problems we find in older homes:1) Pipe material that has been determined to be prone to failure and no longer used, 2) Pipe material and fixtures that are at the end of their serviceable lifespan, and 3) Defective repairs made by the homeowner or a handyman.

1) Pipe material that is prone to failure and no longer used - Polybutylene pipe is no longer rated for installation by the building code and also no longer manufactured.  It is also called “PB” in the building trade and  was used in residential water supply piping in Florida from 1978 to 1995. It was billed as “the pipe of the future” at first, and its low cost and easy installation made it an alternative to traditional copper water piping. PB was especially prevalent in mobile homes manufactured during the 1980s and early 1990s, but we also see it installed in site-built homes of the same era--occasionally even including estate-type homes in Haile Plantation and similar neighborhoods.

   But throughout the 1980s lawsuits, claiming that defective manufacturing and installation had caused hundreds of millions of dollars of water damage from ruptured pipes, began to mount into the thousands. Although the manufacturers never acknowledged that PB pipe is defective, they eventually agreed to fund a class action settlement for just under a billion dollars to resolve homeowner claims. The period for filing a claim ended in 2007.

   While the exact cause is uncertain, it is believed that the oxidants (such as chlorine) in public water systems react with the plastic, causing it to flake and become brittle. As the integrity of the piping deteriorates, tiny fractures develop, which can expand over time and cause a sudden failure of the pipe and resulting water damage.

   Galvanized steel is another type of pipe material that is no longer installed for water supply piping, although still available and used for repairs of existing systems. It was often used for water supply piping in homes until the early 1970s, but not used today because corrosion problems limit it’s useful lifespan to between 40 and, at best, 50 years. Rust-corrosion accumulates inside the pipe and causes a plumbing version of arteriosclerosis, with the gradual hardening-of-the-arteries narrowing the diameter of the pipe in horizontal runs to the size of a soda-straw in places.

    Essentially, it rusts from the inside out. This restricts the flow of water to faucets and showers and, eventually, the corrosion causes the pipe to spring leaks--usually the first place being in the ground under the home’s concrete floor slab, or near the water heater due to an electrolytic reaction to copper fittings speeding up the corrosion. 

The photo below shows the end of an abandoned section of galvanized pipe in a laundry room wall, where it was cut-off at the juncture with a washing machine faucet. As you can see, the water flow was severely reduced from the buildup of rusty crud in the pipe. Surrounding it is the cream-color plastic pipe that replaced it, called CPVC. 

   Both PB and galvanized pipe may be problematic when you apply for homeowner’s insurance for an older home. Some companies will not write a policy for homes with PB or galvanized, and others require a licensed plumber to certify that the pipe system is in satisfactory condition.

2) Pipe material and fixtures that are at the end of their serviceable lifespan - Every component of a home has an average lifespan. Sometimes it will last longer than the average and, then again, occasionally it fails sooner. Here’s some plumbing life expectancies:


          Copper - 60 to 80 years

          Galvanized Steel - 40 to 50 years

          CPVC and PVC - 40 to 50 years

          PEX - 40 years


          Cast Iron - 50 to 65 years

          Galvanized Steel - 40 to 60 years

          Copper - 60 to 80 years

          PVC - 50 to 70 years


          Water Heaters - 10 to 20 years

          Faucets - 15 to 25 years

          Sinks, Tubs, Toilets - 40 to 80 years

          Shut-off Valves - 20 years

   Advanced deterioration of plumbing is easy to spot. The photo at the top of this blog is old galvanized steel pipe that is clearly showing its age, with heavy corrosion and beginning to leak. In other instances, the piping or fixture may look younger that its known age; but, as plumbing approaches the the end of it’s estimated lifespan, you should expect replacement soon. Water shut-off valves have a rating of 20 years because they tend to be frozen in the open position at that age. Your home inspector will note any plumbing that is visibly deteriorated, but inspectors do not test shut-off valves.

3) Defective repairs made by the homeowner or a handyman - Just because a professional plumber did not do all the plumbing work in a home does not automatically mean that it is bad. However, we practically never see incorrect plumbing installation by a licensed plumber. Sink drain configurations that would make even Rube Goldberg laugh occasionally happen when a non-professional tackles a home renovation project.  Traps installed backwards or doubled-up, poorly secured pipes, unvented drains, and unsafe water heaters are common. 

   Also, accordion-type piping is a sure sign of amateur plumbing work.  The photo below shows a homeowner’s sink drain repair using accordion pipe as a tailpiece, connected to three P-traps in a configuration that is absolutely guaranteed to clog.

Although home improvement and hardware stores sell the stuff and it makes easy work of connecting two pipes that are not aligned, the pipe is not rated for installation by any plumbing codes and the ridges collect hair and debris. Here again, your home inspector can help you sort through any haphazard plumbing repairs and determine what needs to be redone.

    Because the age and condition of an older home’s plumbing components do not always correspond with the age of the house or a date of renovation, a careful evaluation of the system is always a sensible part of the due diligence necessary in buying a home.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • 

  To learn more strategies for getting the best possible home inspection, here’s a few of our other blog posts:

How can I make sure I don't get screwed on my home inspection? 

How thorough is a home inspector required to be when inspecting a house?

Should I trust the Seller's Property Disclosure Statement?

Can I do my own home inspection?

How can homebuyers protect themselves against buying a house over a sinkhole? 

The seller gave me a report from a previous home inspection. Should I use it or get my own inspector? 

    To read about issues related to homes of particular type or one built in a specific decade, visit one of these blog posts:

What are the common problems to look for when buying a 1940s house?

What are the common problems to look for when buying a 1950s house?

What are the common problems to look for when buying a 1960s house?

• What are the common problems to look for when buying a 1970s house?

What are the common problems to look for when buying a 1980s house?

What are the common problems to look for when buying a 1990s house?

What problems should I look for when buying a country house or rural property? 

What problems should I look for when buying a house that has been moved?

What problems should I look for when buying a house that has been vacant or abandoned?

What are the most common problems with older mobile homes?

What do I need to know about a condo inspection?

What are the "Aging In Place" features to look for when buying a retirement home?

    Visit our HOME INSPECTION, PLUMBINGCOMMON PROBLEMS, AND OLDER AND HISTORIC HOUSES pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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