Building a Pool on a High Water Table in South Louisiana

Written by Big Easy Pool Designs

The Constraint That Shapes Everything

Quick Answer: In much of the New Orleans metro, groundwater sits close to the surface. A pool excavation is a large hole below grade, so it frequently reaches wet ground, and that single fact drives most of the technical decisions in a local pool build. It affects how the hole is kept workable, what shell type makes sense, how the pool is backfilled, how it must be maintained, and what happens if it is ever emptied. A builder who does not plan for it produces a pool that either costs more than quoted or fails later.

The condition is not uniform. Ground near the river, in older parts of Gretna, or out toward LaPlace behaves differently than higher ground on the Northshore around Covington. Your lot gets assessed on its own.

Dewatering During Construction

When an excavation reaches groundwater, the hole fills. Crews cannot place steel or shoot gunite into standing water, so the water table has to be temporarily lowered around the excavation and held down until the shell is in and can resist the pressure.

That is dewatering, and it is normal work here. What matters for you as a buyer is that it appears in the quote and that the contract is clear about how it is billed if conditions are worse than expected. A bid that ignores it is a bid that will change.

Discharge matters too. Pumped groundwater has to go somewhere acceptable, not simply into a neighbor’s yard.

Hydrostatic Pressure and Why Pools Float

Here is the physics that surprises people. A pool shell is a sealed vessel in the ground. When the surrounding soil is saturated, groundwater exerts upward pressure on the underside of that shell. Full of water, the pool is heavy enough to stay put. Empty it, and the weight holding it down disappears while the upward pressure does not.

The result can be a shell lifting, cracking, or tilting out of position. This is not a hypothetical in South Louisiana. It is the main reason to treat draining a pool as a specialist operation rather than a weekend task.

The Hydrostatic Relief Valve

The standard defense is a hydrostatic relief valve installed in the pool floor during construction. When external groundwater pressure exceeds the pressure inside, the valve opens and lets groundwater into the shell, equalizing the two and preventing uplift.

It is a small component doing an important job. Where a pool has one, it needs to be functional, and where an older pool does not, draining is considerably riskier.

Never Drain Casually

The practical rule for owners in this metro: do not fully drain your pool without talking to a builder first. That includes after a flood event, when the instinct to empty and clean is strongest and the ground is at its most saturated.

Legitimate reasons to drain exist, such as resurfacing during a remodel or resurface. They are done with groundwater conditions assessed, dewatering in place if needed, and the work sequenced so the shell is not sitting empty longer than necessary. This also matters after storms, covered in hurricane season pool prep, where draining is exactly the wrong instinct.

How Groundwater Affects Shell Choice

Construction types respond differently to these conditions, which is why the comparison is worth doing properly in what type of pool material is best. A heavy gunite shell has mass working in its favor. A lighter shell is more sensitive to uplift and depends more on correct installation and backfill. Whichever type, backfill material and compaction around the shell matter, because poorly placed backfill both settles and channels water.

Decking and Settlement

The soil issue does not stop at the shell. Delta soil settles, and the deck around a pool is a large flat surface where any settlement shows immediately as a lip, a dip, or ponding water.

Building the deck on a properly prepared and compacted base is what keeps it level, and a segmental surface like pavers tolerates minor movement better than a rigid slab, since individual units can be lifted and reset without a visible patch. That tradeoff is covered in landscaping ideas for a pool area.

Drainage Around the Pool

A pool and its deck add a large impervious area to a yard that may already drain poorly. Where that water goes needs designing, not assuming. Water pushed toward the house is a much bigger problem than a soggy lawn, and standing water around a pool deck is both a nuisance and a mosquito issue.

Frequently Asked Questions

Can I have a pool if my water table is high?

Yes. Most metro pools are built in these conditions. It changes methods and cost, not feasibility.

How much does dewatering add?

It depends on conditions, depth, and duration. Ask for it to be itemized and ask how variation is handled.

What if my pool has already lifted?

Stop and get it assessed before doing anything else, including refilling. The remedy depends on how far it moved and what damage occurred.

Do I need a relief valve?

In this region it is the standard protection for a shell that may ever be emptied. Ask whether your design includes one.

Is a deeper pool a problem?

Deeper excavation reaches groundwater sooner and costs more to keep dry. That is one reason depth drives price here more than elsewhere, as covered in what an inground pool costs.

Get Your Lot Assessed

We look at ground conditions before designing, so the pool that gets quoted is the pool that can be built on your property without surprises during excavation.

Big Easy Pool Designs serves the metro and Northshore. See inground pools, custom pool design, or call (504) 688-4066.