The Albuquerque Swamp Cooler Fall Shutdown Checklist, Neighborhood by Neighborhood

September 4, 2026

Albuquerque’s swamp coolers have one enemy that outworks all the others, and it shows up on a different date depending on where you live. The National Weather Service office in Albuquerque publishes average first fall freeze dates by station, and they spread across nearly three weeks: October 17 in Corrales, October 21 at Los Lunas, October 23 in the foothills, October 24 in the South Valley, and November 3 at the Sunport. The earliest freeze the Sunport has ever recorded was September 18, 1912. The reason for the spread, in the NWS’s own words, is that on calm nights the valley floor can be 10 degrees or more colder than the airport, which is why the growing season is 210 days at the Sunport and only 161 in Corrales.

Every one of those dates is a night that can split the quarter-inch water line running up the side of your house. This post is the checklist for making sure it does not, with the timing for each part of the metro. It takes about 30 minutes on the roof and it prevents the single most common spring repair we do.

First, the date

These are drain-by dates, not freeze dates. Draining is reversible. If a warm week comes back, you can turn the water on again in ten minutes. A split copper line cannot be turned back on.

If a hard freeze is forecast earlier than any of these, drain that evening. The record early freezes are real: September 18, 2006 in Corrales, September 19, 2006 at Los Lunas, September 25, 2000 in the foothills.

The checklist

1. Shut the water off at the source

Find the shutoff for the cooler line. It is usually a small valve at a hose bib or a saddle tap on a water line in the utility area, sometimes in the crawl space. Close it. If it does not close fully or it is a saddle valve that has seized, that is the first repair on the list, because it is the valve you need in a hurry when the float fails next July.

2. Drain the line

Shutting the water off leaves the line full. Go to the cooler, open the union or compression fitting where the line enters, and let it drain. On a long run, blow it clear with a shop vacuum on blow or a few breaths of compressed air. Water left in the line is exactly what freezes, expands, and splits the pipe or blows the fitting. Nothing leaks in January because everything is frozen and the water is off. It leaks in April when someone opens the valve, and if the split is inside the wall, the drywall finds it first.

3. Drain the pan

Pull the drain plug or open the drain valve on the pan and let it empty onto the roof. Then scoop out what is left. Third-party compilations of the Albuquerque Bernalillo County Water Utility Authority’s 2024 zone water quality reports put the system average at 141 milligrams per liter, about 8.2 grains per gallon, with zones from 45 to 243; Rio Rancho’s aquifer water tests near 180. Every gallon the cooler evaporated this summer left that mineral in the pan, and a pan that sits wet for five months turns it into a crust that eats next year’s pump. Scrape it, wipe it, let it dry.

4. Pull the pads

Aspen pads come out and go in the trash; they are done. Rigid media comes out, gets rinsed, dried completely, and stored dry, or left dry in the unit. Wet pads under a cover all winter grow the mold that produces the swamp smell at start-up. If the pads are so scaled they crunch, they were done in July anyway.

5. Check the pump and float

Lift the pump, clean the intake screen, and spin the impeller by hand. If it is stiff or crusted, note it: that pump is a spring replacement at $150 to $400 installed, and knowing now means the right one is on the truck in April. Check that the float moves freely and the arm is not bent. A stuck float is a dry pan and a dead pump next June.

6. Oil nothing, note everything

Bearings get oiled at start-up, not shutdown, because oil sitting all winter collects grit. But look at the belt for cracks and glazing, and listen for the blower wheel wobbling when you spin it by hand. Write down what you saw. The spring start-up is where it gets fixed.

7. Cover it

A fitted cooler cover, strapped so the mesa wind does not take it in February. It keeps snow, leaves, and roof grit out of the pan and blower, and it keeps birds out of the down-duct. On the exposed mesa in Rio Rancho and the north slope in Placitas, check the straps twice.

8. Seal the damper

This is the step everyone skips, and it is the one that shows up on the gas bill. The down-duct from the cooler ends at a ceiling register in the hall. Close the damper and cover the register with a fitted cover or a piece of insulation board taped in place. A cooler with an open damper is a hole in the roof all winter; the house’s heated air goes up the duct and out through the cooler. In a house with both a cooler and refrigerated air, common across the Northeast Heights where a second system was added to a 1960s house, an unsealed damper leaks conditioned air all summer too. Seal it now, open it in April.

9. Close the window relief

If the house relies on a window cracked for cooler relief, close and lock it. Obvious, and skipped every year.

What skipping it costs

The math is short. A professional shutdown is $100 to $200. Skipping it produces, in a typical April:

• A split water line, repaired with the start-up visit.
• A pan that rusted while it sat wet, which on an older unit is a replacement conversation at $1,500 to $4,000 installed.
• A pump seized in the crust, $150 to $400.
• Pads that molded, $80 to $200 for aspen or $300 to $700 for rigid media that would otherwise have lasted two more seasons.
• A winter of heated air leaving through an open damper.

And all of it is discovered in the first hot week of May, when every schedule in the metro is full and the repair waits.

Landlords, especially

Since the City Council’s 2025 amendment to the Uniform Housing Code, ordinance O-59, Albuquerque rental units must have working cooling that holds habitable rooms at or below 80 degrees measured three feet above the floor, and the ordinance counts evaporative coolers. A landlord with coolers on four roofs who skips the fall shutdown is buying four split lines and four spring repairs in the same week tenants start calling about the heat. A shutdown round in October and a start-up round in April is the cheap way to stay ahead of it.

When to hire it instead

If the roof is a steep two-story in Rio Rancho, a flat roof with no parapet access in Nob Hill, or you are one of the quarter of Bernalillo residents over 65 and the ladder is not appealing, hire it. Many crews package the shutdown with the spring start-up at $120 to $250, and the tech who drained the cooler in October knows exactly which pump to bring in April. The full table is on the pricing page. Send a photo of the cooler and the roof access, and you get a time before the valley freezes.