What is the average life expectancy of copper pipe?

Friday, July 27, 2018

Copper water supply pipe should last 50 to 70 years, and possibly longer. Unfortunately, “aggressive” acidic water or soil can cause pitting-type corrosion and shorten the lifespan to 20 years or less. Also, other combinations of alkaline ph, hardness, and contaminants can activate pitting, which is essentially the dissolving of copper ions into the water flow at spots on the pipe wall. In extreme cases, the water is tinted a green-blue from the copper leaching. 

    Water with a neutral ph (7.0) is ideal for the long life of copper piping. Our local water company, Gainesville Regional Utilities (GRU) rated the ph of water leaving the treatment plant is 8.6 (slightly alkaline, due to the dissolved karst in our aquifer) in a recent annual report. But when we test the water at the kitchen faucet during home inspections, the average ph is closer to 7.0, possibly changed by the distribution pipes.

    Copper was the standard choice for water pipe in North Florida from the early 1970s to about 2000, when CPVC (a cream-color plastic) pipe became more popular, largely due to its resistance to pin-hole leaks caused by pitting, the less-expensive material cost, and somewhat easier installation. 

   The lifespan of the copper pipe is also affected by the grade of pipe installed. There are three grades:

  • Type K - 0.049 inch thick wall, recognizable by green lettering on pipe
  • Type L - 0.040 inch thick wall, recognizable by blue lettering on pipe
  • Type M - 0.026 inch thick wall, recognizable by red lettering on pipe

    Both L and M are commonly used in residential construction. Obviously, Type L pipe’s thicker wall means a longer lifespan, but Type M is the predominant one installed. Patina formation on the surface may make it difficult for you to identify the lettering color on older pipe.

    In our area, we primarily find leakage under the floor slab. Copper pipe should be set in clean fill sand under the floor slab when the house is constructed, because the acidity of regular black soil will accelerate the pitting. “If the pipe was not bedded properly in sand, or cheap copper pipe was used, under-slab leaks can start as early as 10-years after the house was built,” according to James Freeman, of J.W. Freeman Plumbing.

    Another cause of copper pipe leakage is shown below, in the compartment under a master bathroom spa tub. “The green area on the pipe is from the acidic flux that was used to make the solder joints not being wiped off after the joint was made,” says James. “And the white crud buildup is a very small active leak that leaves water-mineral deposits behind as the water leaking out evaporates.” You can also see more of it in a small pile on the floor below the leak.

   To understand the basis, potential use, and limitations of lifespan ratings, see our blog post How accurate are the average life expectancy ratings of home components? Are they actually useful? 

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Here’s links to a collection of our other blog posts about PLUMBING PIPES:

How can I protect my pipes to keep them from bursting during a hard winter freeze in North Florida?

Can galvanized steel pipe still be used for new water lines in a house? 

How can I tell if I have cast iron pipes in my house? 

Why can't a sanitary tee be used for a horizontal-to-horizontal drain pipe connection? 

Is a washing machine drain hose required to be secured at the standpipe?

What are the abandoned pipes sticking out of the wall in my house?  

What are the code requirements for plumbing vent terminations?

What are the code requirements for layout of drain piping under sinks?

What causes a gurgling sound when a bathtub or sink drains? 

What is a "combination waste and vent" in a plumbing system? 

What is a building trap?  

What is a galvanized nipple?

What are the pipes sticking out near my water valves?

How do you accurately find a broken water pipe leak under the floor slab?

What is the difference between water pipe and sewage (waste) pipe? 

Are plastic pipes (PVC, CPVC, and PEX) safe for drinking water? 

Is a hot water faucet handle required to be on the left? 

What is a dielectric union? 

What's that powdery crust on the pipe connections at the water heater? 

If all the plumbing drains have water in them and you can still smell sewer gas, what's causing the problem?  

How can I tell what type of plumbing pipe I have?

Why is there a flexible accordion pipe under the sink? 

What is the difference between PVC and ABS plumbing pipe?

What is the difference between water service pipe and water supply pipe? 

What are the pipes on my roof? 

What is a P-trap?

Why is old galvanized steel water pipe a problem for homebuyers?

What does polybutylene pipe look like? Why is it a problem? 

• Which water pipes are an insurance problem and possibly uninsurable?

• Can you connect CPVC pipe directly to a gas water heater?

    Visit our LIFE EXPECTANCY and PLUMBING 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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