GSI Drilling

GSI Drilling, the trading name of Gretton Site Investigations Ltd, specialises in borehole drilling for water supplies and ground-source heat pump systems across the UK and Channel Islands. The company works with both domestic customers and larger commercial projects, drawing on more than 19 years of drilling experience and a fleet of 11 rigs.

Its services include water well and water borehole drilling, geothermal and ground-source heat pump boreholes, soakaway installation and dewatering. The team can assess suitable drilling locations, work in difficult ground conditions and confined spaces, install pumps and complete water systems. Water projects include casing, well screens, flow measurement and water-quality checks, with a no-water, no-charge policy advertised for qualifying drilling work.

GSI also supports larger and time-sensitive projects with multiple rigs and drilling teams, including construction and commercial work. Its equipment includes newer lower-emission rigs suitable for low-emission zones, while the team highlights experience in challenging sites such as inner London and other restricted-access locations.

The company presents itself as a family-run, hands-on drilling team. Site staff are described as CSCS members, NPORS-trained and first-aid trained, with many having several years of experience. Whether you need a private water supply, geothermal drilling for a heat pump, a soakaway or construction dewatering, GSI offers project-specific advice and quotations.