Underground Service Colour Codes in NZ: A Marking Out Guide for Civil Contractors
Underground service colour codes tell every crew on site what’s buried below before a single spade goes in. Before an excavator breaks the surface, crews locate and mark every existing service in the work area: power, gas, fibre, water, wastewater and stormwater. Get the mark wrong, or let it fade, and the result is a service strike. That can mean injury, a damaged asset, a halted site, and a repair bill far larger than the job.
Spring is when this work peaks. The ground dries out, civil programmes reopen, and crews across the country need marking out product in the same fortnight.
The Underground Service Colour Codes
Each service type has its own colour, so anyone on site can read the ground at a glance:
| Underground service | Colour |
|---|---|
| Electricity | Orange |
| Gas | Yellow |
| Telecommunications / fibre | Purple |
| Potable water | Blue |
| Wastewater / sewer | Red |
| Stormwater / drainage | Pink |
Always confirm service locations against the asset owners’ plans before marking. Request plans through beforeUdig , and check the requirements set by each utility operator.
Why Marking Out Paint Matters for Underground Service Colour Codes
Underground service colour codes only work if the marks stay legible. Marks have to last through rain, foot traffic and machinery until the work is finished, sometimes for weeks. Four things matter most.
Inverted spray. Marking out is done at ground level, so the can must spray upside down, with a steady pattern down to the last of its contents.
Adhesion to any surface. Services cross grass, gravel, dirt, concrete, timber and bitumen, often on the same job. One product needs to hold on all of them.
Fade resistance. A mark that fades before the digger arrives is a mark that failed. Solvent-based formulations give a permanent, fade-resistant finish outdoors.
Colour accuracy. Consistent, clearly distinguishable colours keep the code readable, including in low light or on dark surfaces.
MAC SprayMark Upsidedown Paint
MAC SprayMark Upsidedown Paint is a 500ml solvent-based inverted aerosol built for this work. Its high-delivery valve and wide spray tip handle both spot marks and writing, and it dries fast to a permanent, fade-resistant finish on grass, gravel, dirt, concrete, wood and bitumen. It comes in a range of colours for underground service colour codes and site coding, and is NZ-made and supplied to civil, council and contracting crews nationwide.
The same product is used by forestry and harvesting operations for ground and setout marking, where marks have to survive rain, sap and handling.
Also this September
Spring brings other priorities for NZ sites. Treat wasp and ant activity while nests are still small. Stock personal insect repellents for outdoor crews before sandfly season peaks. Run cockroach and bed bug programmes in accommodation before occupancy climbs . And plan Q4 volumes with your distributor before the December shutdown.
Frequently asked questions
What are the underground service colour codes in NZ?
Under NZ underground service colour codes, orange marks electricity, yellow marks gas, purple marks telecommunications and fibre, blue marks potable water, red marks wastewater, and pink marks stormwater.
What paint do contractors use for marking out underground services?
Contractors use inverted aerosol marking paint, which sprays upside down for ground-level work. It should be solvent-based and fade-resistant, and adhere to grass, gravel, concrete and bitumen. MAC SprayMark Upsidedown Paint is made for this purpose.
How long does marking out paint last?
Solvent-based inverted marking paints give a permanent, fade-resistant finish designed to stay visible outdoors for the duration of the works. Actual life depends on surface, weather and traffic.
Talk to our team for product advice and documentation. We’ll connect you with your nearest distributor.
Talk to our team for product advice and documentation. We’ll connect you with your nearest distributor.