Swamp coolers (evaporative coolers) are still everywhere in the older Las Vegas Valley. They are cheap, efficient when humidity is low, and easy to maintain. They also sit on your roof, run gallons of water through their systems daily, and quietly leak into attics when something fails. After the late spring startup season, our crews see a predictable wave of ceiling water damage calls from homes with neglected coolers.
This guide covers what fails, what to inspect each spring, the warning signs from inside, and how restoration handles a typical swamp cooler ceiling loss.
Why so many Vegas homes still have swamp coolers
Evaporative coolers (swamp coolers) are still common across the older valley, especially in North Las Vegas, Sunrise Manor, parts of east Henderson, and 1960s to 1980s ranches around the central core. They are cheap to run, but they sit on the roof and they constantly handle water, which is a recipe for slow ceiling damage when components fail.
How a swamp cooler causes water damage
Three failure modes account for almost every claim our crews see.
- Float valve failure: the float sticks open and the unit overflows continuously. Water runs onto the roof and finds any seam.
- Pan rust through: the galvanized water pan rusts at the seams over the years and leaks straight into the attic insulation.
- Supply line freeze split: the 1/4 inch copper supply line splits during a winter freeze, and water flows the next time the cooler is started in spring.
Spring startup checklist
Five minutes on the roof in April prevents most claims. If you are not comfortable on a roof, hire a local HVAC tech for a $150 spring service.
- Inspect the pan for rust, pinholes, or sediment that holds water against the metal.
- Test the float by pushing it down and confirming water shuts off cleanly.
- Check the bleed off line; clogged bleed lines are why pans fill with mineral sludge.
- Inspect the copper supply line for green corrosion or splits at the saddle valve.
- Reseal any roof penetrations around the cooler base.
Warning signs from inside the house
The first symptom is often a faint stain on the ceiling directly below the cooler, or a musty smell when the cooler kicks on. By the time drywall is sagging or paint is peeling, the attic insulation above is usually fully saturated and needs to come out.
- Yellow or brown ring on the ceiling under or near the cooler
- Drywall texture that feels soft or spongy to the touch
- Musty odor that intensifies when the cooler runs
- Visible water tracking down a wall under a cooler shroud
What restoration looks like
Our crews tarp the roof if needed, remove saturated attic insulation, dry the framing and ceiling drywall to dry standard, treat for mold, then rebuild ceiling drywall, texture, paint, and re-insulate. Most ceiling water damage losses from a swamp cooler dry in three to four days. We coordinate with your HVAC contractor so the leak source is fixed before the ceiling goes back up.
Why pan rust through is so underrated
Float failures are dramatic and obvious; pan rust through is the silent killer. Galvanized water pans hold water 24/7 during cooling season, and the joints rust from the inside. By the time a pinhole opens at a corner seam, water has already been dripping into the attic insulation below for days, soaking it through, and starting to wick into ceiling drywall. A single afternoon on the roof in April with a flashlight catches this every time.
When the loss reaches the living space
Once you see a ceiling stain, the attic insulation directly above is almost always saturated and has to come out. Wet insulation has zero R value and grows mold quickly in the closed attic environment. Our crews remove the affected insulation, dry the framing and drywall to dry standard, treat for microbial growth, then rebuild ceiling drywall, texture, paint, and re-insulate to current code.
Need professional help with this in Las Vegas or Clark County? Our IICRC-certified crews respond 24/7.
Call (702) 605-2526