Supply Plumbing in Older Homes

When inspecting older homes, I often find quite a variety of plumbing supply materials. Copper is the old reliable dating back to the 1930s and still is in use today, although to a lesser extent due to cost.

Older Types

Lead was used until the 1930s, but due to health issues related to lead exposure and ingestion, it luckily found its way out of the plumbing world as a supply material.

Galvanized steel is still found today in older homes, although it is almost always now found with other materials (such as copper, CPVC, PEX, etc.). When certain dissimilar metals meet, they can react with each other and quickly corrode the pipe material, leading to leaks. Copper and steel are two such metals. Therefore, whenever copper and steel meet, a dielectric union should be installed between them. A plastic or rubber gasket actually separates the two metals so they can not touch.

Copper became much more common in the 1930s and has been in use ever since. It has a long-lifelife expectancy compared to some other plumbing materials.

Galvanized steel, for example, may last only 40 or 50 years before it has rusted through. Also, when galvanized steel rusts, it expands approx. 8 times its original size. Therefore, a galvanized steel pipe that had an inner diameter of 1” when new, may only have an inner useful diameter of 1/8”. This is often the reason for low water flow at bathroom or kitchen sinks in older homes. Keep in mind that most of the home’s plumbing is hidden in walls, ceilings, or flooring and that the plumbing material you see under the sink may not be the only plumbing material supplying water to that fixture. Copper pipe may be visible under the sink although within the wall, there may also be galvanized steel pipe.

Water flow issues

When the flow is low enough to declare it insufficient for normal use, it’s often time to call in a licensed and qualified plumber to evaluate the system. Replumbing, at least, part of the home may be the plumber’s recommendation. In a large home with a high amount of still functioning galvanized steel pipe, the cost to replumb may be quite high.

Another possible cause for low flow at kitchen and bathroom sinks can often be fixed rather easily. If the spigot’s aerator is clogged with sediment, this can drop the flow way down. Carefully unscrewing the aerator should show if sediment is indeed limiting the water flow. I tend to find this issue more commonly in homes with wells since they can easily pick up sediment from the well. A sediment filter in-line with the well’s pressure tank can help prevent this issue. That’s not to say sediment can’t clog aerators in a home with public water, but it’s less likely.

Other options beyond copper

While copper has been the standard supply pipe material for the past 70 or so years, the price of copper has risen the past few decades making other materials much less costly. It doesn’t seem that we can go a month or two without hearing a story on the TV news of someone breaking into a vacant home and stealing the copper pipe and wiring.

A material called polybutylene (or “PB” for short) came out in the 1970s and was supposed to be the next greatest thing. This material came in several colors, although the most common color in this area is grey. It normally will have “PB2110” printed on it every few feet.

The plastic pipe material didn’t require soldering and it was bendable, and this allowed for lower labor costs. Pieces of PB pipe are mechanically fastened to each other with metal or plastic fittings, while copper pipe and its fittings are soldered together. After some use, however, polybutylene was found to have issues itself. It is believed that the when hot chlorinated water passes through this material, it causes the fittings to become brittle and corrode which can lead to leaks. Different types of PB fittings have come out, however the material was taken off the market around 1995 after a $950 million classaction lawsuit settlement. There was also a 2nd class-action lawsuit as well. Both classactions have since expired (run out of money). Personally, I see polybutylene in maybe 5% of the homes that I inspect. Interestingly, I’ve only ever seen PB pipe leak once in over 21 years inspecting homes. Based upon the size of the class action settlements, PB pipe obviously has its issues regardless.

Chlorinated polyvinyl chloride (CPVC) became popular in the 1960s and is still in use today. This material is primed and glued to its fittings with special cement products. Since there are no mechanical fasteners, such as what polybutylene uses, CPVC is quite durable and long lasting. This material can be used for hot and cold water, whereas it’s ‘cousin’ Polyvinyl Chloride (PVC) is only rated for cold water. I occasionally find PVC installed as the discharge pipe on a water heater’s temperature/pressure (T&P) valve; that is a faulty and potentially hazardous installation.

In the 1980s, a new pipe material called PEX or Cross-linked Polyethylene became popular in the US and is still in regular use today. In most new or recent construction that I inspect today, I commonly find PEX or CPVC. PEX comes in clear, white, and red and blue varieties. The red and blue color coding makes it easier for plumbers to fish the pipe through walls and ceilings to ensure the proper pipe is connected at the other end to either hot or cold water. The only difference between red and blue PEX is purely the color. A PEX plumbing system is assembled using mechanical or compression fittings. Another advantage of using plastic plumbing materials over copper is that much more heat is lost from hot water through copper than the plastic materials, which can lead to energy cost savings. Energy loss due to copper piping can be lessened to some degree by installing pipe insulation over the material. Pipe insulation can be purchased at most hardware stores and is quick and easy to install.

As with any type of plumbing in the home, I always suggest to my clients that they regularly check any accessible plumbing (basement ceiling, under sinks, etc.) since it’s always better and cheaper to fix a minor leak than a big one that’s been going on for a while.