How deep do you need to dig for a pool?

How deep you need to dig is determined by the pool model’s design, substructure, and planned height in the garden. The water depth is not the same as the excavation depth. Use the installation drawing for the pool you are actually going to build.

Three measurements that need to be kept apart

• Water depth: the distance from the water surface to the pool’s finished bottom.
• Construction height: the pool frame’s dimensions from the lower edge to the upper edge according to the drawing.
• Excavation depth: the distance from the chosen ground reference to the bottom of the excavation, including space for the required substructure.

If the top edge of the pool is to be above the existing ground, that affects how much needs to be excavated. The coping and adjoining deck also need to be coordinated with these levels. Therefore, use a shared height reference when the pool supplier and the ground contractor review the drawing.

The pool type affects the substructure

A thermopool, a PP pool and a fibreglass pool can have different requirements for the base, support, and backfill. The dimensions must be taken from the selected model’s instructions. A general allowance of a certain number of centimetres does not suit all constructions.

Assess the ground and access before excavation

The load-bearing capacity of the ground, rock, groundwater, and how water will be drained away need to be assessed on site. Also plan working space around the pool, routing of utilities, and how spoil will be removed. Check existing utilities before digging begins. Ask the contractor to clarify what conditions the quote is based on and how unexpected ground conditions are handled.

Check the project’s permit requirements

Check with the municipality regarding the rules for ground changes, decking, walls, and pool enclosures in your project. There is no general municipal standard depth that can replace the pool's installation drawing. The National Board of Housing, Building and Planning describes the requirements for fixed basins and pools.

Prepare this for the quote

Gather the pool’s dimension drawing, desired finished height, photos of the site, and access information. Ask for a breakdown of excavation, removal, substructure, water drainage, and backfill. Also read our overview of cost factors when building a pool.