A soil test is not paperwork for its own sake. It tells your builder how the ground under the pool is likely to behave once excavation starts, including strength, drainage and how soils move with moisture.
Testing is especially useful on sloping blocks, reactive clay, filled land, and sites with a high water table. The report guides excavation method, base preparation and drainage so the fibreglass shell stays properly supported.
A DIY hole is not the same as a geotechnical report. Port Pools By Design uses site conditions on the NSW Mid North Coast to decide when engineering advice is needed before we dig.
Identifying ground issues early is usually cheaper than dealing with movement or drainage problems after the pool is in.