Swamp Cooler or AC Leaking on the Roof?
When water comes in under a swamp cooler or an air conditioner on the roof, either the unit is making or spilling the water, or the roof around the unit is letting rain in. The unit is a job for its own technician, and the roof around it, where the unit sits and where its ducts and lines go through, is a roofing job.
Call or text photos to (725) 502-3114 for a free, no-pressure inspection and a written estimate before any work begins.
Two different leaks
A unit on the roof can put water on your ceiling in two ways. The unit can make or spill water: a swamp cooler runs on water, and an air conditioner makes condensation that has to drain away. Or the roof around the unit can let rain in through a hole, a seal or flashing that has failed.
An air conditioner or plumbing problem is not a roofing job. If the unit is leaking, call its technician. The roof side is ours to find and fix. Sometimes both are going on: the unit spills water, and that water finds a gap in the roof under it.
Start with the timing
If the stain grows on hot, dry days while the unit is running, think of the unit first. Condensation from cooling equipment and ducts happens in hot weather, and a cooler uses water all day.
If the stain grows only when it rains, the roof around the unit is the likely source. If it grows in both, there may be two problems.
Our article on telling a roof leak from an air conditioner or plumbing leak has more checks you can make from inside the house.
Where the roof around a unit fails
Every unit needs holes in the roof: a duct opening, and often lines for water, power or drainage. Each hole depends on flashing or a seal. In the desert, sealants dry and crack, and rubber hardens and splits.
On a flat roof, a unit usually sits on a raised curb or a stand. The roofing turns up the curb, and that joint needs watertight flashing. On a flat roof, water that sits against it after rain, or drips on it from a unit all summer, finds any weak point.
On a pitched tile roof, a cooler stand rests on the tile or is fastened through it, and the people who service the unit walk on the tile around it. Wind and foot traffic crack and dislodge tiles. That exposes the underlayment to direct water and sun.
Old units leave holes behind. When a cooler or air conditioner is removed or moved, its old opening has to be closed and sealed. Unsealed penetrations left behind by old antennas or air conditioner work can leak, because the hole was never closed properly.
Water a unit puts on the roof
A swamp cooler can overflow, drip from a worn pan or line, or drain water onto the roof through a bleed line. An air conditioner's condensate line that ends on the roof wets the same spot day after day.
Water that runs over the same spot every day wears at the roofing, and on a flat roof it can stand around the unit. Hard water also leaves mineral crust where it dries. Where the unit's water goes is a question for the unit's technician. What it has done to the roof is a question for a roofer.
What you can check safely
Stay off the roof. Desert roofs are hot and slick with grit, and around a unit there are wires and water as well.
Inside, note when the stain grows, and whether the unit was running or it was raining. If the air handler is in the attic or a closet, look at its drain pan and drain line outlet. Standing water in the pan, or a drain line that is dripping or backed up, means the air conditioner is making the water.
From the ground, look for water running off the roof near the unit on a dry day, a line dripping onto the roof, or streaks on the wall below. Take photos of the stain inside and of the unit from the ground.
What we do on the roof side
We trace the leak from the stain back to the roof and check the penetrations, the flashing and the roofing around the unit, along with the other usual suspects on that path. We check for old penetrations as part of roof leak detection, because they are a common cause of leaks that other repairs missed.
When we install a flat roof, it is a reflective TPO or PVC membrane with sealed penetrations and watertight flashing at every wall and curb. See our TPO and PVC roofing page.
We show you what we found and why it leaks. If the checks point away from the roof, an air conditioning technician is the right call, or the cooler's own technician. Every leak repair we perform is backed by a 5-year warranty.
A repair or a bigger job?
Resealing a penetration, fixing a flashing edge or replacing a few cracked tiles can be a small repair. If water has been running under the unit for a long time, the underlayment around it may need replacing too.
On a flat roof that has reached the end of its life, or where water stands around the unit after every rain, a new reflective TPO or PVC membrane may be the better answer. We will tell you honestly whether your roof needs a targeted repair or has reached the end of its service life. Our article on flat roof leaks covers standing water and drains.
Frequently Asked Questions
Is a swamp cooler leak a roofing problem?
The cooler itself is not. Its pan, float and lines are for its own technician. The roof around it, where it sits and where its lines go through, is a roofing job.
How do I tell an AC leak from a roof leak?
Timing. An air conditioner leak follows hot weather while the unit runs. A roof leak follows rain.
My old cooler was removed. Can the roof still leak there?
Yes. The opening it left has to be closed and sealed properly. Unsealed penetrations from old antennas or AC work are a common leak source.
Should I go up and look at the unit?
No. Desert roofs are hot, steep and slick with grit. Look from the ground and from inside, and send photos.
Who do I call?
For the roof around the unit, call or text photos to (725) 502-3114. For the unit itself, call its technician.