Condensate Leak in the Attic in San Leandro

Condensate Leak in the Attic in San Leandro

Air conditioning produces water. The coil condenses humidity out of the air, it drips into a pan, and a drain line carries it outside. When the line clogs or the pan fails on an attic-mounted air handler, the water lands on the ceiling below. A brown stain spreading across a hallway or bedroom ceiling is how most homeowners find out, often well after the leak started.

San Leandro's housing is largely post-war: 1950s through 70s single-family across Marina Faire, Estudillo Estates, and the central neighborhoods. Most of these homes are on their second or third HVAC system, but the condensate setup is often a patchwork of whatever each installer improvised. We commonly find drain lines run uphill, float switches left out, and emergency pans that were never connected to a safety. The climate is mild near the bay, warmer inland, so AC runtime is moderate, but a moderately used drain still clogs over a couple of decades.

Almost every one of these leaks is a single repair, not a system replacement. We trace the real cause before quoting, and the fix lands on a written estimate so the price is clear up front.

Common causes

Clogged primary condensate line. Years of summer use grow slime inside the drain until it plugs. Water backs up over the pan edge. We clear it with a wet vac, flush it, and add a capped access tee so it can be maintained. On San Leandro's older installs the original drain often has no service access at all, which is why these go unnoticed until they overflow.

No float switch, or one that was never wired. A working float switch shuts the AC off when the pan fills, before any water reaches the ceiling. On homes this old we routinely find no safety switch, or one sitting in the pan with its wires never connected. We test what's there and install a properly wired switch so the next clog stops the system instead of staining drywall.

Improper drain pan slope from an old install. Decades of repair work mean the air handler may have been reset without the right pitch toward the drain. Water pools at the wrong end and seeps through a seam. We level the unit and shim it so it drains to the outlet. This is one of the more common finds on San Leandro's much-serviced older systems.

Rusted or cracked drain pan. A metal pan under an aging coil rusts through; a brittle secondary pan cracks. Either lets water skip the drain entirely. We inspect both with a light and a moisture check, and we're honest about whether pan service makes sense given the age of the rest of the system.

Failed condensate pump on a closet install. Where a closet air handler can't gravity-drain, a small pump moves the water out. When that pump fails, the pan overflows quickly. We test the pump under power, check the discharge tubing and check valve, and confirm its safety float is wired to shut the AC down on overflow.

How we diagnose it

• Trace the ceiling stain back to the attic or closet air handler and rule out roof and plumbing leaks with a moisture meter.
• Open the air handler and inspect the primary, secondary, and emergency pans for standing water, rust, and cracks.
• Test the float switch, or install one if the original install never had a working safety.
• Clear and flush the primary drain line and verify flow at the outdoor termination.
• Check and correct pan slope, since decades of prior service often leave the unit out of level.

$75 diagnostic, credited toward any repair over $200. You get a written quote before any work begins.

Condensate Leak in the Attic in San Leandro: common questions

Nearby and related

Condensate Leak in the Attic near San Leandro: Oakland · Hayward · Castro Valley .

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