Condensate Leak in the Attic in Daly City

Condensate Leak in the Attic in Daly City

An attic air handler's condensate has to travel further and through more turns than a garage or closet unit, so when the drain path fails, the water usually shows up as a ceiling stain before anyone notices a mechanical problem. The common causes are a clogged primary drain line, a cracked or corroded pan, a failed condensate pump, or a float safety switch that never cut power to stop the overflow. We trace the water to confirm it is condensate and not a roof or plumbing leak before opening anything up. The detail that matters in Daly City is the fog that made central air rare here in the first place and the Doelger tract homes built without ducts.

Local housing stock affects how an attic drain path was built and how it fails. Daly City sits under some of the thickest, most persistent fog in the Bay Area, rolling in off the ocean through the gap near Colma and holding through most summer afternoons. Genuine no-AC-needed days outnumber real heat days most years here. The Westlake district's Doelger-built tract homes from the 1940s and 50s make up a huge share of the city, block after block of nearly identical houses that went up with no ductwork and no central air, because nobody building here in 1955 planned around cooling. Newer construction toward the BART corridor and the hills near San Bruno Mountain breaks that pattern.

In Daly City, we confirm the source of the water before opening anything up, because an attic leak that turns out to be a roof or plumbing issue needs a different call entirely. Once we've confirmed it's condensate, the written estimate covers the drain, the pan, or the pump, whichever failed. The $99 diagnostic fee is credited toward the repair.

Common causes

Clogged primary condensate line. Algae and dust build up inside the line over the years until it backs up faster than it can drain, and the water finds the path of least resistance, usually straight through the attic-access ceiling.

Failed or undersized condensate pump. Where gravity cannot carry the line to a drain, a pump lifts the water out. A failed pump, or one that was undersized for the unit, leaves water with nowhere to go but over the pan.

Cracked or corroded primary pan. Pans crack and corrode with age, and the failure often only shows up under a full running cycle rather than sitting empty.

Float switch that never cut the system. The float switch exists specifically to shut the system down before an attic overflow becomes a ceiling stain. When it sticks or fails, that safety net is gone.

Improper pan slope from a settled install. A pan that has shifted out of level after the install settles no longer drains fully and leaves standing water that eventually finds a way out.

How we diagnose it

• Trace the water source to confirm it is condensate from the attic unit, not roof flashing or a plumbing line above the ceiling.
• Open the air-handler access panel and inspect the primary pan for rust-through, cracks, and standing water.
• Test the float switch by lifting the float to confirm it actually shuts the system off.
• Clear and flush the primary drain line, then watch the pan empty fully under a running cycle.
• On pump-assisted units, run the condensate pump under load and check the float and check valve.

$99 diagnostic, credited toward the repair. You get a written quote before any work begins.

Condensate Leak in the Attic in Daly City: common questions

Nearby and related

Condensate Leak in the Attic near Daly City: South San Francisco · Pacifica · San Bruno .

This is usually a ac repair in Daly City job. See our ac repair overview or the Daly City service area.