What's under a Lafayette backyard
| Soil | Where you find it | Wet season (USDA) |
|---|---|---|
| Coteau | Slightly higher, gently rounded ground | Saturated at 1.5–3 ft for up to a month in winter and spring |
| Patoutville | Broad, nearly level terraces | Wet below 0.5–3 ft; slow permeability |
| Jeanerette | Flats and slight dips | Wet below 1–2.5 ft, December–April |
| Frost | Depressions and drainageways | Wet below 0–1.5 ft, December–April; collects runoff from higher ground |
| Judice | Clayey low spots; first described in Lafayette Parish | Perched water at 0.5–1.5 ft, December–April |
USDA Official Series Descriptions. Your lot may be different: the excavator finds out on day one.
Why an empty pool can rise
The weight of the water keeps a pool seated. Take it out while the ground around it is saturated, and upward pressure can beat the weight of the shell. Fiberglass is lightest and most at risk; concrete tends to crack instead (Shotcrete, 2025).
Relief valves
A hydrostatic relief valve in the main drain lets groundwater in when the outside pressure is higher, which takes the strain off the shell. It helps, but the trade press warns it's "not a cure-all" (Aqua Magazine). Ask if your bid includes one and keep a note of it for future service calls.
Zero net fill and your spoil pile
After the August 2016 flood, when the Vermilion River ran backward and newly built Youngsville neighborhoods went under (64 Parishes), LCG adopted zero net fill in November 2017. In the floodplain, any fill brought in must be offset by storage taken out, and all development in the city and unincorporated parish needs a permit (LCG). For a pool, that usually means trucking the dirt away instead of building up the yard. LCG's floodplain office, 337-291-8468, can say how it applies to your lot.
Rules for owners
Common questions
Is groundwater a problem when digging a pool here?
Often, from December to April. The silty soils around Lafayette drain slowly; USDA describes Frost soils, common in low spots, as wet within 0–1.5 ft through those months (USDA). Expect pumping during a winter dig and ask for a hydrostatic relief valve.
Can I empty my own pool?
Not without your builder. An empty shell on wet ground can be pushed upward, and fiberglass, being light, is the most exposed (Shotcrete, 2025). Leave the job of lowering the water more than a foot to the people who built it.
What is zero net fill, and does it affect my pool?
Since November 2017, Lafayette Consolidated Government has required that development in the floodplain not reduce flood storage: in LCG's words, bring one bucket in and take one bucket out (LCG). A pool dig makes a lot of dirt, so on a floodplain lot plan on hauling it off rather than raising the yard. Ask LCG how it applies to yours.
Sources & further reading
- USDA soil series: Frost
- USDA soil series: Patoutville
- USDA soil series: Coteau, Jeanerette, Judice
- LCG: building within a floodplain. Zero net fill
- 64 Parishes: the 2016 floods
- Shotcrete: dewatering pools (2025)
Editorial note: General planning information, not engineering or legal advice. Prices are estimates; confirm current rules with your local officials and a qualified pro.