Civil drainage contractors in the Waikato and Taupō
Stormwater and wastewater mains, HDPE pipelines, manholes and shored trenching on council, subdivision and commercial sites. Built to the engineer's design and signed off. We don't do residential drainage.

What drainage work does Trident Earthmoving do?
We do civil and infrastructure drainage across the Waikato and Taupō: stormwater and wastewater mains, HDPE pipelines welded in house by a certified poly welder, manholes, chambers and shored trenching, all built to the engineer's design and signed off by the engineer. We don't do residential drainage. If you need a main laid to grade through a live site, we are the right call.
Where the water goes
Our drainage work is civil and infrastructure. Stormwater and wastewater mains, welded HDPE pipelines, manholes and chambers, and the shored trenches they go in, on council, subdivision and commercial sites where the design is engineered and the sign-off is formal. We don't do residential drainage. If you need the drains on a house connected, we're not the right call. If you need a main laid to grade through a live site, we are.
Welded in house
Scott holds HDPE poly welding certification, so polyethylene mains and pipelines are welded by our own crew rather than waiting on a subcontractor. One less trade on site, and one less thing holding your programme up.
Shored where it needs to be
For deep trenching we use trench shields rather than battering the whole thing back. Safer, and it means we can work in tight corridors and close to existing services without opening up half the site.


Get the water away from it
We lay stormwater and wastewater mains, including large diameter precast pipe, and build the manholes, chambers and outfalls that go with them. Where the design calls for polyethylene, Scott is a certified HDPE poly welder, so welded pipelines are done in house rather than waiting on a subcontractor.
Trenches are shored to depth with trench shields, levels come off the model with grade control, and every job is built to an engineer's design and signed off by the engineer. On rural and roading jobs we also do the drainage that goes with the earthworks: culverts, crossings, table drains and subsoil drainage on races and tracks.
How a drainage job runs
- Read the drawings. Inverts, grades, pipe spec and where it outfalls, before we price anything.
- Quote the scope. Excavation, shoring, pipe, bedding, backfill and reinstatement, clearly separated.
- Set up the site. Service locates, traffic management where it's a live carriageway, shields on site for the depth.
- Trench, bed and lay. To grade off the model, welded or jointed to spec, bedded and haunched properly.
- Engineer sign-off. Inspected and signed off, then backfilled in layers and reinstated.
What does drainage work cost?
Civil drainage is priced on depth, ground and what's around the trench more than on pipe length. A short deep run through a live road can cost more than a long shallow one across a paddock. These are the things that move the number:
- Depth. Decides how much spoil comes out, whether the trench needs shields, and how big a machine has to be on site.
- Ground and water. Rock and running sand both slow a trench right down, and a high water table can mean dewatering before anything can be laid.
- Pipe and jointing. Precast concrete, PVC and welded HDPE all price differently, and the design sets which one it is.
- What is in the way. Live services, traffic management and working next to existing structures all mean careful digging rather than open trenching.
- Reinstatement. Putting a paddock back is quick. Putting a carriageway or a footpath back to council spec is not, and it belongs in the quote rather than as a surprise.
We quote off the drawings with reinstatement included, so the price you get is the price to finish the job, not just the price to dig the trench.
Where we work
Based at Whakamaru, we cover Taupō, the South Waikato, Waipā, Hamilton and out to Rotorua and the King Country. Here is the patch, and what we tend to see on the ground.
Common questions
Still not sure? Give us a call and we will talk it through.
Always. Civil drainage is built to the engineer's drawings and levels, then inspected and signed off by the engineer. Grade control on the machine means the inverts match the design rather than being close enough.
Yes. Scott is a certified HDPE poly welder, so welded polyethylene mains and pipelines are done by our own crew rather than a subcontractor. Fewer trades on site, and less waiting around.
No. We don't do house drainage or private drainage work. Our drainage is civil and infrastructure: stormwater and wastewater mains, HDPE pipelines, manholes and shored trenching on council, subdivision and commercial sites, built to an engineer's design and signed off by the engineer.
Yes. Backfill and reinstatement are part of the job, not an extra. We would rather find a problem before we leave than leave you one.
Contact us
Tell us what you are dealing with and we will come and size it up.












