AC Leaking Water in Los Altos, CA | Bay Area HVAC Service

AC Leaking Water in Los Altos

An air conditioner makes water on purpose. The evaporator coil pulls humidity out of your air and that condensate is supposed to run down a drain pan, into a PVC line, and outside. When you find water around the indoor unit, one of those steps stopped working. The cause is almost always a single part: a clogged drain line is by far the most common, but it can also be a cracked pan, a stuck float switch, or a coil that froze and is now melting.

A lot of Los Altos homes make this more likely for a specific reason. The big single-story ranch footprints here often put the air handler up in the attic to save floor space. An attic handler drains the long way, sometimes a good run of PVC with a couple of slope changes, and any of that run can clog with algae and dust over a few seasons. When it backs up, the water has gravity on its side and a finished ceiling right underneath.

The good news is the fix is usually cheap. Most of the time we are clearing a line or swapping a small float switch or pan fitting. The expensive scenario is when a leak gets ignored for a week or two and soaks drywall or insulation. That is why we tell people to shut the system off and call rather than keep running it while water finds the ceiling. Our diagnostic is $75, credited toward any repair over $200, so you see the part and labor on a written estimate before we touch anything.

Common causes

Clogged condensate drain line. The most common cause by a wide margin. Algae and dust build a plug in the PVC, water backs up into the pan, and overflows. On Los Altos attic handlers the long horizontal runs make this worse. We clear the line with a wet vac at the outdoor termination and a nitrogen or CO2 blowout, then flush it and confirm flow at the pan.

Full or cracked secondary drain pan. Attic units sit in a galvanized or plastic safety pan with its own drain. If that pan rusts through or its drain is plugged, water hits the attic floor. We inspect the pan condition, clear the secondary drain, and if the pan is cracked we replace it. A pan full of standing water is a sign the primary line failed first, so we chase both.

Stuck or failed float switch. A float switch is supposed to shut the system off when water rises in the pan. When the switch fails closed, the AC keeps running and overflowing. When it fails open, it nuisance-trips and you lose cooling. We test the switch, confirm it cuts the call for cooling, and replace it if it is sticking. This is a small part that prevents big ceiling damage.

Frozen evaporator coil melting off. Low refrigerant or weak airflow lets the coil ice over. When the system cycles off, that ice melts faster than the pan can drain and water pours out the front. We check refrigerant charge with gauges and inspect the filter and blower. If a system is oversized for the home, short cycling can also frost the coil.

Disconnected or slipped drain line. PVC drain joints that were dry-fit or glued poorly can separate, especially in an attic that bakes all summer. The line looks intact but is dumping condensate next to the unit instead of outside. We trace the full run, find the break, and re-glue or replace the fitting.

How we diagnose it

Shut the system down and find the actual water source, whether it is the primary pan, the secondary pan, or a slipped line.
Pull and inspect the air filter and check blower airflow, since restricted air is a top cause of the coil freezing.
Clear and flush the condensate line, then pour water through the pan to confirm it drains all the way outside.
Test the float switch to confirm it cuts the cooling call when the pan fills.
Read refrigerant pressures and coil temperature with gauges if there is any sign of icing.

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

AC Leaking Water in Los Altos: common questions

Do you actually cover Los Altos, or just the Tri-Valley?

We cover Los Altos and the broader South Bay along with our home base around San Ramon. We route by where our techs are that day, so a Los Altos call gets handled out of our South Bay coverage. Call (925) 999-4095 and we will give you an honest window, not a vague all-day promise.

It is mild here. Is a leaking AC even worth fixing fast?

Los Altos summers are moderate, but a leaking drain is a water problem before it is a cooling problem. Water sitting on an attic floor or running down a finished ceiling does damage whether it is 85 or 105 outside. The repair itself is usually small. The drywall and insulation it ruins if ignored is not.

There is water but the unit still blows cold. What is happening?

That usually points to a clogged drain. The AC is cooling fine and making condensate normally, but the water has nowhere to go and is overflowing the pan. Shut it off so it stops adding water, and we will clear the line. If it were a refrigerant or coil-freeze issue you would usually also notice weaker cooling.

Nearby and related

AC Leaking Water near Los Altos: Palo Alto · Mountain View · Cupertino .

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