APWA Utility Colors

The color for storm drains is purple. I used to live where there were combined sewers, but no longer do. 

Posted by: @not-my-real-name

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The color for storm drains is purple.

Our city has a non-potable "purple pipe" water supply system that parallels the potable system. The water they deliver is used for fire protection and irrigation, as needed, of certain wetlands in summer. The color purple is used for that. While not all that common, these purple pipe systems are far from unknown. The locaters use green for both storm and sanitary hereabouts.

@norman-oklahoma Purple is the "official" APWA marking color for "slurry, irrigation and reclaimed water"

It's important to remember that most marking using APWA colors are tied to one-call marking which exist for damage prevention (read liability exchange) not engineering purposes.  So, the colors really just exist to give excavators an idea what will be there, and they can use their "judgement" to help determine where. For example, they know that generally potable water is below the frost line and comms for traffic signals is at "ditch witch depth".

Interestingly (given the training most one-call marking crews have), I know of at least one state that forbids anyone except one-call contractors to mark utilities in the public right-of-way using APWA colors. So, on a public contract I can perform weeks of utility research including as-built requests, send out a utility designator with twenty-years' experience, and have a PE and a PLS review and certify to that work, and not be allowed to use APWA colors. But Bobby One-Call, from 811 low bid contract holder Spray and Pray, Inc, with two days training in how to operate his equipment and no real knowledge how utilities are installed can.          

Yeah purple is irrigation around here too.

Potable water and storm drain are painted dark blue if I remember right but I separate them in cad.

@norman-oklahoma

I the areas I work the APWA color code is the standard. I agree that a new and individual color for storm drains should be added. 

Years ago, I was taught that the APWA colors were chosen to signify the danger level of hitting the utility.  I'm not sure how true that is but it makes sense for power and gas.  If you hit a power line with a shovel, you're going to get shocked.  If you break open a gas line chances are good you will get burned (I have seen a 5/8"IR hammered through a 4" poly gas line without a fiery result).  When you dig through a gravity line, worst case is that you release brown trout into the environment.

 Back on topic, a good locator will indicate SS or SD on the green lines.

@cv That or seems like it should be painted purple over blue.

Actually, it doesn't matter what color they paint if it's almost always wrong. 

Posted by: @john-putnam

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a good locator will indicate SS or SD on the green lines.

The use of the colors doesn't stop at the painting. Utilities are buried with color coded locator tape or wire. That helps the locator know just what he is locating. Gas lines themselves are usually yellow. Sanitary PVC pipe is green.  Fiber Optic conduit is orange.  Plus, there is an issue of colors to be used in CAD. 

@norman-oklahoma When I designed my own template I made my cad colors exactly the same as the apwa scale.  Never could figure out why survey or engineering companies didn't do this too, or at least the ones I worked at never did this.

Posted by: @bstrand

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Never could figure out why survey or engineering companies didn't do this

In the beginning CAD colors equalled a pen, of a certain thickness, in the plotter. So color equalled lineweight.  If, for example, green was set to be the 0.70mm pen, you couldn't really use green for all your sewer drawing needs. These old habits of colors being associated with pen weights is still engrained in a lot of heads - mostly heads that are multiple generations seperated from knowledge of why that is so.   

Posted by: @norman-oklahoma

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These old habits of colors being associated with pen weights is still engrained in a lot of heads - mostly heads that are multiple generations seperated from knowledge of why that is so. 

Yeah, that's how it's been everywhere I've worked.  The dumb thing is the color/lineweight combos aren't even the same from one company to the next so it STILL makes no sense. 🤣