Utility Graffiti

Look around and you'll notice them. Different colored lines and symbols spray painted all over the ground. They are so common on roads, sidewalks, and lawns that you probably don't think twice when you see them. 

These marks identify the existence of underground utility lines. The purpose is to keep people safe while digging. Driving a shovel into an electrical line or accidentally excavating a natural gas pipe is not a happy kind of surprise. The colors and symbols are a warning and signify imminent construction, but they are also a code for what lies beneath our day-to-day world.

The "Uniform Color Code" was created by the American Public Works Association (APWA) to standardize the use of utility markings across the country. Each type of utility has its own color. The most common are red for electric, yellow for gas or petroleum, orange for communications, blue for water, and green for sewers.Symbols are often used to denote the width of the utility line. 

I find utility markings fascinating because they are a map to a subterranean world that we know is there, but can't otherwise visualize. Sometimes the map confirms what you might expect…

Like power lines running into a big ugly green transformer. Other times you get a glimpse of the unknown... 

Like this pipeline of water running under a walking trail I frequent. 

And here we can see where a natural gas line crosses beneath a road. 

You might see faded green or blue lines on the curb outside each house in your neighborhood. They identify where water goes in or the sewer line comes out, the remnant of some completed construction project. Marks like the one below one can be found on curbs all over indicating the flow of some vital resource. 

One of the most-interesting things I've discovered is the identification of manholes. 

There's one! Green indicates a sewer access manhole, but there are manholes for communication, water, and electric. I found a variety of interesting examples. 

My unconfirmed speculation is that the circled manhole cover with the slash through it means it is inaccessible. The pink numbers are a survey location marking, perhaps applied to the manhole cover because it will fade faster. Particularly intriguing is the last picture of what I can only assume is a buried manhole.

The purpose of these utility markings is to save lives and prevent injury and damage, but they also present an interesting opportunity to those of us just passing by. We get a glimpse into the presence of the vital network of cables, wires, and pipes running beneath us. This network carries our water, electricity, telecommunications and entertainment, and much more. It's the lifeblood of our world and remains largely invisible most of the time. Check out the map sometime.

- Nick

@MrVigabool