How to clear window weep holes before the rain

Updated November 5, 2026. By Landen Chu, Co-founder of OakTend. How we research

Weep holes are the small slots or holes along the outside bottom of many window frames, especially sliding and vinyl windows. Rain that gets into the bottom track drains out through them. Some windows have a second hole inside, under the track.

How often: Check them every fall before the first big storm. Milgard says a good time is whenever heavy rain is on the way, and suggests vacuuming the tracks now and then.
What you need: Vacuum with a crevice tool, Cup of water or spray bottle, Soft brush, Pipe cleaners or a thin drain brush, Putty knife, Compressed air (optional)

Why it matters

Water collecting in a sliding window's track is normal, Milgard says, which is why the track and its weep holes need to stay clear. In Orange County, dust has the whole dry season to settle in them, and the National Weather Service describes Santa Ana winds as dust-bearing. Then most of the year's rain arrives December through March. If the holes are clogged or have been caulked shut, the U.S. Department of Energy's Building America Solution Center warns, water can build up inside the frame and damage the wall framing, sheathing and insulation. This job belongs with the November rain prep on our Orange County home maintenance checklist.

Steps

Outside, look along the bottom of each window frame for small slots or flat holes. Inside, check under the sliding track for a second hole.
Vacuum the dirt and grit out of the inside track.
Pour a cup of water into the track, or mist the outside of the glass, and watch the outside slots. The water should run out of them.
If caulk or paint covers a slot, carefully cut it away with a putty knife.
Loosen dirt at each opening with a soft brush or a pipe cleaner. Pull it out toward you rather than pushing it deeper into the hole.
Work a pipe cleaner or thin brush through the channel. A short puff of compressed air from the inside hole can help.
Pour in water again. If it still does not drain, clean the track once more or try a different tool.
Wipe the frame with mild soap and water. Milgard warns that abrasive or acidic cleaners can permanently damage the finish.

Sliding patio doors have weep holes too, and the same steps work. While you are at the doors, see how to replace door weatherstripping.

When to call a pro

Call a window installer if water still will not drain after cleaning, if water shows up on the inside sill, wall or floor under a window, or if you see stains, peeling paint or soft wood around the frame. If the window is still under warranty, contact its maker first.

Safety

Work from inside and from the ground. If the outside of an upstairs window can only be reached from a ladder or by leaning out, clear it from the inside and leave the outside to a pro. Skip acetone, which the Building America Solution Center notes can damage surfaces, and never caulk or paint over the slots.

Go deeper

This is general information, not professional advice. Your equipment's manual comes first when it says something different.

Sources

Milgard: window and door care tips
Windows and patio doors have a weep drainage system with slots on the exterior bottom of the frame; water building up on the sill or outside track is normal, so keep the track clean; inspect the weep holes and clear them with a soft brush; a good time to do it is when heavy rain is expected; occasionally vacuum the tracks; never use abrasive or acidic cleaners on the frame. Checked 2026-11-05.
Milgard: how to clean weep holes on a vinyl sliding door
Sliding patio doors have weep holes that let water run out of the door track, and Milgard recommends cleaning them. Checked 2026-11-05.
U.S. Department of Energy Building America Solution Center: clean window weep holes
Weep holes are slots at the bottom of the exterior frame, often with a second hole under the interior track; clogged or caulked weep holes let water build up in the frame and damage framing, sheathing and insulation; test by pouring water into the track or misting the glass; remove caulk with a putty knife; avoid pushing debris further in; clear the channel with a pipe cleaner, brush or compressed air; retest; acetone can damage surfaces. Checked 2026-11-05.
National Weather Service glossary: Santa Ana wind
Santa Ana winds are strong, hot, dust-bearing winds that descend to the Pacific coast. Checked 2026-11-05.
NOAA National Centers for Environmental Information: 1991-2020 monthly precipitation normals, John Wayne Airport
Most of the year's rain (8.89 of 11.18 inches) falls December through March. Checked 2026-11-05.

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