Your Swamp Cooler Is Running Nonstop in This Heat Wave: Where the Water and the Leaks Actually Go

Las Vegas is grinding through another stretch of triple digit days with overnight lows barely dipping into the 80s. If your home still runs an evaporative cooler, this is exactly the kind of week that turns a slow leak into a soaked ceiling and a surprise water bill.

A Heat Wave That Isn't Giving the Valley a Real Night

Las Vegas hit 114 degrees at Harry Reid International this week, its hottest day of the year so far, and forecasters have kept an extreme heat warning in place with little relief in sight through the coming days. Highs are expected to hold in the 110 to 112 degree range before building back toward the mid-110s over the weekend that follows.

The part meteorologists keep flagging is not the daytime number, it's the overnight one. Lows are sitting in the upper 80s to low 90s across much of the valley this week, compared with a typical late-July low closer to 83, which means nothing in or around a house gets much of a chance to cool off before the next hot day starts.

Why This Kind of Stretch Is Hard on an Evaporative Cooler

A swamp cooler that would normally cycle on and off through a mild afternoon ends up running close to around the clock during a heat wave like this one, and that extra runtime puts real wear on the small parts that keep it working correctly. The float valve that controls the water level in the reservoir is doing far more work than usual, and it's exactly the kind of part that tends to stick, either running dry or overflowing, after days of nonstop use.

Las Vegas tap water also leaves mineral scale behind as it evaporates off the cooling pads, and that buildup accelerates on a unit that barely gets a rest. Scale can clog the small pump, the distribution tray, or the tubing that feeds water to the pads, which is often the moment a float valve that used to work fine finally sticks open.

The Water Waste That Shows Up on the Bill, Not on the Ceiling

A rooftop cooler with a stuck float valve doesn't always announce itself with an obvious drip inside the house. Sometimes the first sign is a water bill that jumps for no reason anyone in the house can explain, because the overflow is running quietly off the roof or pooling somewhere it isn't noticed right away.

When it does show up indoors, it's usually a stained ceiling tile, a soft spot near a roof penetration, or a musty smell in a hallway closet below where the unit sits. Any of those, especially appearing for the first time during a heat wave this long, is worth walking outside to check rather than waiting for it to dry out on its own.

What to Check Before the Next Round of Triple Digits

The good news is that most of what fails on a swamp cooler during a heat wave is inspectable from the ground or a quick trip up a ladder, and catching it early is far cheaper than a ceiling repair. The same goes for a water heater that has been quietly working overtime in a hot garage all week.

If you're not sure the last time anyone looked at your cooler's float valve, pump, or pads, or your water heater is past the eight to ten year mark, don't wait for the next 110 degree day to find out the hard way. Kingdom Plumbing has served Las Vegas homeowners since 2018 under Nevada license 0085422. Call (702) 213-6112 for an inspection while there's still time to fix it before it fails.

6 Checks for Evaporative Coolers and Water Heaters During This Heat Wave

These are the spots that matter most on a swamp cooler and a water heater when the system barely gets a break for days in a row.

1. Check the float valve for sticking: A valve that won't close all the way is the most common cause of a cooler that overflows onto the roof.
2. Look for mineral scale on the pump and pads: Las Vegas tap water leaves buildup that clogs distribution tubing faster on a unit running nonstop.
3. Watch your water bill this week specifically: An unexplained jump can point to a rooftop leak before any drip ever shows up indoors.
4. Inspect ceiling tiles and closets below the unit: Staining, softness, or a musty smell under a cooler are early signs of a slow leak worth catching now.
5. Check the water heater's pressure relief valve: Sustained heat drives thermal expansion that can push an aging valve to weep at the fitting.
6. Know your main shutoff location: If a rooftop line or valve does fail during the heat, knowing where to shut off water fast limits the damage.

Frequently asked questions

Do evaporative coolers actually waste a lot of water during a heat wave?

They can, mainly through a stuck float valve or scale-clogged tubing that causes overflow, which runs continuously the longer the unit operates without a break.

Why would my swamp cooler start leaking now when it worked fine in the spring?

Extended nonstop operation during a heat wave puts far more wear on the float valve and pump than the shorter, intermittent runtimes of milder weather.

Should I turn my evaporative cooler off during extreme heat to protect it?

Not necessarily, but it is worth checking the float valve, pump, and pads now rather than waiting, since the unit is under more stress than usual.

Does Las Vegas's hard water make cooler problems worse?

Yes. Mineral scale builds up as water evaporates off the pads, and that buildup accelerates on a cooler running long hours during a sustained heat wave.