Engineering-Led Subsurface Insight in Nelson, New Zealand
SSGS is an independent, Nelson-based specialist providing utility location services and geotechnical support across the Top of the South.
Our Story
Founded in 2025, Subsurface Geoservices and Solutions (SSGS) was created to address a recurring issue in construction and infrastructure projects: subsurface uncertainty identified too late in the process. On small-to-medium projects in particular, early and accurate underground information has a major impact on safety, programme, and cost.
SSGS exists to reduce that uncertainty, delivering clear, technically defensible subsurface information that supports confident decisions before drilling, excavation, or construction begins.
Our purpose is simple: Provide clear, factual, and practical subsurface information that supports safer, more efficient construction.
Driven by Passion
SSGS is led by Ryan O’Toole, an Engineering Geologist with over 20 years of international experience delivering geotechnical and subsurface services across New Zealand, Ireland, the UK, and Australia.
Ryan’s experience spans the full lifecycle of subsurface investigation and construction support — from utility locating and mapping, hands-on site investigations, and drilling supervision, through to technical reporting, operations management, and quality assurance.
Ryan has held senior roles including Senior Engineering Geologist, Operations Manager, and Laboratory Technical Manager. These roles required direct accountability for field delivery, data quality, safety systems, and client outcomes — experience that now underpins the engineering-led approach of Subsurface.
Local Knowledge. Practical Outcomes.
Based in Nelson and working across the Top of the South, SSGS combines Ground Penetrating Radar, electromagnetic locating, sonde tracing, CCTV pipe inspection, and geotechnical field support with experienced engineering judgement.
Understanding local geology, infrastructure age, and legacy service challenges allows investigations to be targeted and proportionate. The goal is straightforward: undertake the right level of investigation at the right time, clearly communicate uncertainty, and reduce risk before work begins.
A Highly Qualified Team
Subsurface Geoservices & Solutions is prequalified through SiteWise, demonstrating our commitment to robust health and safety systems aligned with industry best practice.
Ryan O’Toole is also a member of Nulca New Zealand, the industry association representing underground service locators throughout NZ.
What Our Clients Are Saying
“Ryan brings a level of practical judgement that’s rare in subsurface investigations. The information provided was clear, defensible, and directly usable in our design process. His understanding of both ground conditions and construction realities made a real difference to the project.”
— Senior Civil Engineer, Nelson“SSGS provided accurate service locating ahead of excavation and clearly communicated the limitations. The site markings were precise, and the reporting was straightforward. It gave our team confidence to proceed without second-guessing what was below ground.”
— Project Manager, Civil Contractor“We engaged SSGS early in the project to reduce risk before drilling works began. The advice was practical, measured, and scaled appropriately to the site. Having direct access to an experienced engineering geologist made the process efficient and reassuring.”
— Property Developer, Tasman Region