The short answer: If floodwater reached your water heater’s burner, controls, or elements, replace them; do not relight or re-power the unit. Check gas connections, watch your water meter for hidden leaks, follow boil advisories, and do not pump a septic tank while the ground is still saturated.
The storm passes, the water drops, and then the second wave of damage shows up: the slow, quiet kind. These are the calls that flood our phones at both shops in the weeks after a hurricane or a flash-flood event, in the order you should check them at your own home.
1. The water heater: the most dangerous thing to “just try”
If floodwater touched your water heater, stop before you relight or reset anything.
- Gas units: the gas control valve and thermostat are not built to survive submersion. Water corrodes them from the inside, and a corroded gas valve can fail to shut off. Every major manufacturer and the federal safety guidance agree: flood-exposed gas controls and valves must be replaced, not dried out. If the burner compartment took on water, the safe call is usually a new unit.
- Electric units: flooded thermostats and heating elements short and corrode. At minimum they need replacement and the wiring needs inspection before the breaker comes back on.
- Tankless units: control boards do not tolerate water. If the cabinet flooded, have it evaluated before restoring gas or power.
How do you know how high the water got? Look for a mud line on the tank jacket. If the line is above the lower access panel (electric) or the burner door (gas), treat the unit as compromised. Insurance adjusters look for the same line, so photograph it before anyone cleans.
Yes, this is annoying advice when the unit “seems fine.” It is also the difference between a controlled replacement this week and a gas failure at 2 a.m. in October. If you are unsure, we will look at it and tell you straight; if it is safe to keep, we will say so. When we note water in the insulation of the water heater, rust has already started working its way into the unit, and our recommendation is to change it.
2. Gas lines and connections
Storms shift things: meters, regulators, the soft copper or CSST lines feeding appliances. If you smell gas at any point, leave the house and call from outside. After flooding, have buried gas lines pressure-tested before heavy use; saturated, shifting soil is exactly what breaks them. CSST flex lines deserve their own attention: they are known for pinhole leaks caused by lightning strikes, which our storms supply, so have those lines tested too. This is licensed work (our master gas fitter license is LMNGF #9436), and it is quick compared to what it prevents.
3. Hidden water leaks
Fast saturation and fast drying move Acadiana’s clay soils, and moving soil breaks underground water lines and slab plumbing. The five-minute test: turn off every fixture and appliance that uses water, then watch your meter. If the dial creeps, something is leaking between the meter and your fixtures. A jump in your next water bill is the same signal a month late. We cover the full leak-finding checklist in our water bill guide, and our leak detection team can pinpoint a line break without digging up the yard to find it.
4. Septic systems: the counterintuitive one
Do not have your tank pumped while the ground is still waterlogged. An empty concrete or fiberglass tank in saturated soil becomes a boat; tanks really do float out of the ground, tearing pipes on the way up. Instead:
- Minimize water use until the drain field surface is no longer soggy.
- Expect slow drains for a few days; a saturated field has nowhere to send water.
- If sewage backs up into the house, that is an emergency call.
- Once things dry out, have the tank inspected: floodwater carries silt into tanks and it settles where it does not belong.
5. Drains, sewers, and what the neighborhood shares
Municipal sewers surcharge during floods. If your tubs or floor drains burped water during the storm, or toilets are still gurgling days later, the line between your house and the street may have taken on silt or debris. A camera inspection settles the question in an hour, with video you can keep. Gurgling that will not quit is the classic sign; we wrote a full article on what that sound means.
6. Boil advisories and your fixtures
Follow the advisory until your water system lifts it. When it lifts: run cold taps for several minutes, flush ice makers (dump the first batches), and replace refrigerator and under-sink filter cartridges, which are contaminated by design; they caught what came through.
Frequently asked questions
Can a flooded water heater be repaired instead of replaced?
Anytime we note water that has reached the inner insulation of the water heater, we recommend a full change-out. Water does not dissipate quickly, and anytime moisture meets oxygen, rust is guaranteed to follow. That rust starts devouring your water heater from the outside in, and once it starts, it cannot be stopped.
Will insurance pay for a flooded water heater?
Under flood insurance (NFIP or private), water heaters are generally covered as building property. Homeowners policies exclude rising water. Photograph the mud line and the data plate before removal.
How long after a flood should I wait to pump my septic tank?
Wait until the soil over the tank and field is firm and no longer saturated, typically one to two weeks after water recedes, longer in low-lying areas. Pumping too early risks tank flotation.
Why do my drains still smell after the flood?
Usually a dried or silted P-trap, sometimes sewer gas from a surcharged line. Pour water into unused floor drains first; if the smell persists, see our sewer smell guide or book an inspection.
We do the post-storm check so you do not have to guess
After a storm, Hargrave’s runs a whole-home plumbing check out of both our Lafayette and Youngsville shops: water heater, gas connections, meter test, drains, and septic. One visit, straight answers, photos of anything we find. Book online or call 337-344-3920 in Lafayette or 337-385-9857 in Youngsville.
