From Concept to Cannonball: What to Expect During Your Pool Installation
A behind-the-scenes look at how an inground pool gets built in Minnesota — from the first shovel to the first splash. Step-by-step with photos-worth descriptions from a 35-year Twin Cities pool builder.
What Actually Happens During a Pool Installation?
Building an inground pool is a multi-trade construction project compressed into 2–3 weeks of on-site work. Most homeowners have never seen it done and don't know what to expect — which is perfectly normal. After building pools across the Twin Cities and Western Wisconsin for 35 years, I've refined the process into seven distinct phases, each with clear milestones so you always know where the project stands. The whole experience should feel organized, not chaotic. If your pool builder can't tell you exactly what's happening on any given day, that's a problem. Here's how a typical Paragon installation unfolds.
Phase 1: Excavation (Day 1–2)
This is the dramatic day — a full-size excavator digs the hole for your pool. For an 18x36 pool, we're removing roughly 80–100 cubic yards of earth. The excavation goes deeper than the pool itself because we need room for footings below the frost line (60–80 inches in Minnesota). We also dig trenches for plumbing and electrical runs. This phase is weather-dependent: we need dry conditions for the heavy equipment. The excavated dirt is either spread on your property (if there's room and you want it for grading) or hauled off-site. Expect the excavator, a skid-steer, and a dump truck in your yard. It's loud for a day or two, then it's over. I mark the exact pool location and depth before digging starts — this isn't a phase where you eyeball it.
Phase 2: Footings and Structure (Day 2–4)
Once the hole is dug, we install the foundation. In Minnesota, this means pouring concrete footings on sono tubes set 4 feet on center around the entire pool perimeter. The sono tubes extend below the frost line — typically 5 feet deep — so that frost heave can't lift the pool structure. After the footings cure, the 14-gauge steel wall panels are set on top and bolted together. The walls are triple-braced with steel strapping and horizontal supports. This is the skeleton of your pool, and it's engineered to handle decades of ground pressure, ice expansion, and Minnesota temperature swings. I personally check every footing depth and every wall connection. This is not a phase I delegate.
Phase 3: Plumbing and Electrical (Day 4–6)
With the structure in place, the plumbing crew runs the supply and return lines from the pool to the equipment pad location. All plumbing in Minnesota needs to be installed with drainage in mind — every pipe must slope so water can be completely blown out during winterization. Any low point in the plumbing is a potential freeze-and-crack point. We use schedule 40 PVC for all underground plumbing, with sweep fittings rather than sharp elbows to improve flow and make winterization blow-out more effective. The electrical contractor runs conduit for the pump, heater, lighting, and any automation equipment. A dedicated sub-panel is typically installed at the equipment pad. All electrical work is done by a licensed electrician and inspected by the city.
Phase 4: Backfill and Floor (Day 6–7)
The area behind the steel walls is backfilled with clean granular material — sand or pea gravel, never clay. Granular backfill drains water away from the walls, which is critical in Minnesota where trapped water behind the wall would freeze and push inward. The pool floor is graded with a vermiculite or sand-cement mixture that creates a smooth, slightly cushioned surface for the vinyl liner. Floor grade is critical — low spots hold water under the liner and can cause wrinkling, while high spots create wear points. We laser-level the floor and hand-trowel the finish. It takes experience to get right, and this is another step I personally supervise.
Phase 5: Liner Installation (Day 7–8)
The vinyl liner is custom-measured for your exact pool dimensions and manufactured by Latham — the largest liner manufacturer in North America. Installation requires a warm, calm day (liner material is more pliable in warmth and wind makes handling difficult). We hang the liner from the top of the steel walls using a bead track, then use a shop-vac to pull the liner tight against the walls and floor, removing all wrinkles. Water begins filling the pool immediately after the liner is sealed — we adjust the liner as the water rises to ensure a wrinkle-free fit. This is where 35 years of experience shows. An experienced crew gets a flawless liner fit; an inexperienced crew leaves wrinkles that you'll see every day.
Phase 6: Equipment Installation (Day 8–9)
While the pool fills (which takes 24–48 hours depending on water pressure), we install the equipment: Hayward SuperPump variable-speed pump, Hayward C-4000 filter, Hayward 250K BTU heater, underwater LED lighting, Polaris robotic cleaner, and any additional equipment like a salt chlorine generator or automation system. All equipment is connected to the plumbing and electrical, tested for leaks, and configured. The automatic safety cover (if included) is installed during this phase — the tracks are built into the concrete deck, so the cover integrates seamlessly. We also install the walk-in steps and any ladders or handrails.
Phase 7: Concrete, Chemistry, and Cannonball (Day 9–12)
The concrete contractor pours the pool deck — typically a 4-foot concrete apron around the pool perimeter, with any additional patio or walkway extensions. Concrete needs 24–48 hours to cure before foot traffic, and 5–7 days before furniture or heavy use. While the concrete cures, we balance the water chemistry: adjusting pH, alkalinity, calcium hardness, and sanitizer to their target ranges. We run the filtration system continuously for 48–72 hours to clear any construction debris and distribute chemicals. Then I do a final walkthrough with you: we review every piece of equipment, show you how to operate the pump, heater, filter, and cover, go over the chemistry routine, and hand you our chemical start-up package ($225 value). Then your family jumps in. That's my favorite part of every project — the moment 35 years of work experience delivers a lifetime of summer memories.