A friend called a few months ago and was very excited. He let me know the plastic pipe limitations in southern Nevada had been removed. “Isn’t this wonderful. Hallelujah!” he said.

The Southern Nevada Code Amendments are used in Las Vegas and Clark County. Until the latest edition of the amendments, plastic pipe was limited to buildings of combustible construction. In building code language, that means Type III, IV and V construction — buildings three or possibly four stories in height or less. The limitation applied to plastic water piping and plastic drain/waste/vent piping.

I thought about the change in Las Vegas and immediately thought, “Now wait a second — it is 2015! Why are there still limitations on the use of plastic pipe?”

It may be hard to believe, but limitations still exist on the use of plastic pipe in plumbing systems. Some of these limitations are in areas of the country that may shock you. If you guessed New York City, Chicago and San Francisco, you are correct. All three of these metropolitan cities have some crazy plastic pipe limitations.

New York City does not allow plastic pipe for water piping anywhere. Plastic pipe can only be used in DWV systems in residential buildings up to five stories high. In commercial construction, plastic pipe is prohibited in all applications.

Chicago is actually more restrictive than New York City. The use of plastic pipe for water systems is limited to CPVC for secondary or reclaimed water piping systems. Otherwise, plastic pipe is not permitted for water distribution systems, even in single-family dwellings. For DWV, Chicago limits plastic pipe to residential buildings three stories in height or less. Of course, you have to remember Chicago requires lead and oakum joints for all cast iron inside the building. No-hub still isn’t permitted.

San Francisco allows plastic water piping but limits it to DWV systems in buildings no more than two stories high. Hence, San Francisco has the most restrictive height limitation. However, unlike New York City and Chicago, it allows plastic pipe in commercial construction within the two-story limitation.

If you thought Los Angeles was in the mix, it removed many of its plastic pipe limitations a number of years ago. A few still exist but none similar to NYC, Chicago and San Francisco.

Think twice

You may be wondering, “Where is the craziness with state requirements?” Again, this may shock you, but the states with limitations are Massachusetts, North Carolina and Kentucky. What? Say that again. You read it correctly — Massachusetts, North Carolina and Kentucky.

Massachusetts has no consistency in plastic pipe limitations. CPVC can be used for water piping in residential buildings up to six stories in height. However, PEX only can be used in residential buildings up to three stories. For DWV, plastic pipe is limited to residential buildings no more than 10 stories high. In commercial construction, it lists allowable uses but does not include connections to water closets, lavatories or standard sinks. Basically, plastic is limited to drainage that could damage metallic piping.

So, if you are in Podunk, Mass., working on a strip mall, plastic pipe cannot be used. I use that as an example because it is all I tend to see in strip malls these days. Maybe that is why there aren’t as many strip malls in Massachusetts.

North Carolina only restricts plastic pipe in DWV systems — plastic can be used only in nonhigh-rise buildings. A high-rise is defined as a building having the highest floor more than 75 ft. above the lowest level of fire department access. Interestingly, the state places no such limitation on plastic water piping.

You may be asking, “How many high-rise buildings are there in North Carolina?” You would be surprised how many.

Then we get to Kentucky. It has perhaps the craziest limitations. It limits the use of plastic pipe in DWV systems to stacks 45 ft. in height or less. You read that correctly. It uses the height of the drainage and vent stack. It measures from the ground to where the pipe terminates out the roof. If the stack is 45 ft., 6 in., either you cut off 6 in. or you install metallic pipe.

The Downtown Louisville Partnership tried to have the plastic pipe limitations removed. So, Kentucky’s plumbing board proposed to allow plastic pipe in nonhigh-rise buildings, 75 ft. or less in height to the top floor. However, only the top 45 ft. of plumbing could be plastic pipe. The lower 30 ft. must be metallic pipe. If you are shaking your head after reading such a screwy limitation, I did, too. No one can give a valid reason for this 45 ft. down from the top of the stack, other than to say, “That’s how we’ve always done it.”

Of course, Louisville looks across the Ohio River and sees plastic pipe used in any building in Indiana. It wonders what changes when you cross the river.

Massachusetts and Kentucky are two of the four remaining states that write their own plumbing codes. All the other states have switched to model plumbing codes. The last restriction on the use of plastic pipe in the model plumbing codes was removed in the early 1990s. I know, it’s 2015. Why are any states hanging on to ridiculous plastic pipe limitations?

The limitations are like passing a law that says you cannot drive a Corvette on the highway in particular states. The reason: It has a fiberglass body. Now, does that make sense?

We have had plastic pipe in plumbing systems for more than 50 years. I wonder when all the state and local plumbing codes will finally allow you to use what ever piping material you choose? After all, it is 2015!

This article was originally titled “Restricting plastic pipe” in the July 2015 print edition of Plumbing & Mechanical.