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What the paint on your lot means: locate colours decoded
The code is national, and it is not a local convention
The colours sprayed on your ground before a dig follow the American Public Works Association's uniform colour code, used by locators across the country. That matters on a lot here for one practical reason: whoever marked your ground — a utility crew, a contract locator, a subcontractor from out of the area — is working from the same key. The paint means the same thing in Island Park as it does anywhere else.
| Colour | What it marks | What it means to a machine |
|---|---|---|
| White | The proposed excavation — outer limits, or the centreline and width of a planned installation | Not a utility. This is your own dig, pre-marked |
| Pink | Temporary survey markings | Not a utility either. Corners, stakes, control points |
| Red | Electric power lines, cables, conduit, and lighting cables | The one that kills people. Stop and hand-dig |
| Yellow | Gas, oil, steam, petroleum, or gaseous materials | The other one. Hand-dig, and know where you would run to |
| Orange | Communication, alarm or signal lines, cables, conduit, and fibre | Rarely dangerous, frequently expensive |
| Blue | Potable water | Expensive and disruptive, and it will find your excavation |
| Green | Sewers, drainage facilities, or other drain lines | Unpleasant, and a repair nobody enjoys |
| Purple | Slurry, irrigation and reclaimed water | Uncommon here, but do not assume it is blue |
The two colours that cause the most confusion are white and pink, because neither marks anything buried. White is the dig you asked about; pink is a surveyor's work. An owner who sees a lot covered in white paint and concludes the utilities have been located has read it exactly backwards.
What the marks do not tell you
This is the part that gets people hurt, and it is not intuitive. A locate mark is a horizontal answer to a horizontal question.
- Marks show route, not depth. Nothing in the paint tells you how far down the line sits, and burial depth varies with the original installation, later regrading, and what the ground has done since.
- Marks have a tolerance. A painted line represents an approximate position, not a surveyed one, and the sensible response near a mark is a shovel rather than a bucket.
- Private lines are usually not marked. The line from a meter to a cabin, a run out to a shop, a buried propane line, a well pump feed — these are commonly on the owner rather than the utility, and they are exactly what a rural lot is full of.
- Abandoned lines are still in the ground. An unmarked line is not proof of an empty trench, particularly on ground that has been built on before.
- Marks do not last. Weather, traffic and time take them, and on a lot here a week of rain or a machine working the same ground can erase a set. If they are gone, they are gone — do not work from memory.
Why this is your problem, not only the operator's
Idaho puts the cost of getting it wrong on whoever caused it, and the statute is not long about it:
Any party responsible for damages to an underground facility shall be liable for the cost of repairs.
— Idaho Code § 55-2208(3) (legislature.idaho.gov, retrieved 2026-08-14)
Read that alongside who is holding the controls. On a hired job the operator carries the duty and, if they are set up properly, the insurance behind it. On a rented machine with an owner in the seat, both land on the owner. The 811 notice page covers the notice itself and the window it runs on.
How to use a marked lot properly
- Photograph the marks the day they appear, with something in frame for scale and a recognisable feature for position. It costs nothing and it survives the weather.
- Walk the lot against the marks before the machine arrives, and ask about anything that does not match what you expected to be there.
- Tell the locator about private lines you know of, and expect to have them located separately if they matter.
- Treat white and pink as information, not safety — they are your dig and a surveyor's markers, and neither one is a warning.
- Hand-dig near any coloured mark rather than trusting a bucket to a painted line, particularly red and yellow.
- Re-notice if the marks have faded before you resume. A stale set of marks is worse than none, because it invites confidence.
Where locates sit in the wider order of work on a raw lot is on the site prep page, what the whole job costs is on the cost page, and how deep the various trenches actually run is on the trench depth page.
Common questions
What do the utility marking colours mean?
Under the APWA uniform colour code: white marks the proposed excavation, pink is temporary survey marking, red is electric, yellow is gas and other petroleum products, orange is communications and fibre, blue is potable water, green is sewer and drainage, and purple is slurry, irrigation and reclaimed water.
What does white paint on my property mean?
It marks the proposed excavation — either the outer limits of the dig or the centreline and width of a planned linear installation. It is not a buried utility. Owners who see white paint and assume the lot has been located have read it precisely backwards.
What does pink marking mean?
Temporary survey markings — corners, stakes and control points. Like white, pink does not indicate anything buried. Both colours describe intentions and measurements rather than hazards, which is exactly why they are the two most often misread on a residential lot.
Which locate colour is the most dangerous?
Red for electric and yellow for gas are the two to treat with the most caution. Both call for hand digging rather than a bucket near the mark. Orange, blue and green are more often expensive and disruptive than immediately dangerous, though none of them are cheap to repair.
Do locate marks show how deep a line is buried?
No. A mark is a horizontal answer only — it shows route, not depth. Burial depth varies with the original installation, any later regrading, and what has happened to the ground since. Never infer depth from paint, and hand-dig to find the line.
Are private utility lines included in a locate?
Usually not, and on a rural lot that is a significant gap. Lines from a meter to the cabin, runs out to a shop, buried propane lines and well pump feeds are commonly the owner's responsibility. If they matter to your dig, arrange for them to be located separately.
How long do locate marks last?
Not long. Weather, traffic and machine work all erase them, and a week of rain can take a set. If the marks have faded before you resume work, re-notice rather than working from memory — stale marks are worse than no marks because they invite misplaced confidence.
Who pays if I hit a buried line in Idaho?
Whoever caused the damage. Idaho Code § 55-2208(3) states that any party responsible for damages to an underground facility shall be liable for the cost of repairs. On a hired job that duty and the insurance behind it sit with the contractor; on a rented machine they sit with you.
Does an unmarked area mean there is nothing buried there?
No. Abandoned lines stay in the ground and are frequently not in any locate record, and private lines are commonly not marked at all. On ground that has been built on before, treat an absence of paint as an absence of information rather than as an all-clear.