How to clear window and sliding-door weep holes
Weep holes are small slots at the bottom of window and sliding door frames that let rainwater out. To clean window weep holes, vacuum the track, work a pipe cleaner through the slot, then pour in water and check that it runs out. Never caulk them shut, even if they look like gaps.
How often to clean window weep holes
No federal guide or code sets a schedule. The Building America Solution Center treats this as a job you do when a water test fails or you can see debris, so build it into the times you're already at the windows.
| When | Why |
|---|---|
| Once a year, when you wash windows | A habit you'll keep, and the track is already open |
| Before your rainiest season | The slots need to be clear before they have work to do |
| After exterior painting or caulking | Caulk or paint can seal a slot by mistake |
| After pressure washing nearby | Strong spray can force water past the slots |
| Whenever water sits in a track | That's a clog or a slope problem |
Pay most attention to sliding doors and ground-floor windows, where dirt and splash-back are worst. One forensic report shows a sliding door's lower slot packed with clay. If you live in the South, check for wasps too. The same author says hornets often nest in uncovered slots.
Tools for clearing window weep holes
- A vacuum with a crevice tool
- Pipe cleaners, or a small drain or straw brush
- A crochet hook, wire hook or small flathead screwdriver
- A cup of water or a garden hose on mist
- Compressed air, if you can reach the inside hole
- A putty knife or utility knife, for any caulk over the slot
Know what you're looking for. Standard weep slots are about 3/16 by 5/8 inch or larger, per the same forensic report. Look along the outside bottom edge of the frame for flat slots or small plastic flaps. On the inside, they sit in the track or frame. Not every window has them. Most swinging doors have solid sills and no weep holes at all.
Some openings are breather holes on dual-sash units, not drains. The window industry group AAMA says to leave those open too. If you aren't sure what a hole does, leave it alone.
How to clean window weep holes, step by step
- Open it and look
Open the sash or slider and find the slots in the track. Go outside and find where they exit.
- Run the water test
Pour a glass of water into the track, or mist the outside glass. Some water should come out of the slot.
- Vacuum the track
Remove loose dirt, dead bugs and grit before you touch the slots, so you don't push it deeper.
- Free the opening
Gently pick at packed debris with a hook. Pull it out toward you, not into the frame.
- Clean the channel
Push a pipe cleaner or small brush through the slot and draw it back out. Use compressed air from the inside hole if you can reach it.
- Cut away any caulk
Slice it off with a putty knife or utility knife. A silicone caulk remover or mineral spirits can soften stubborn bits.
- Test again
Pour in more water. If it won't drain, try a different tool, then clean the whole track.
Signs of clogged weep holes
A blocked weep hole can trap water inside the frame, and that water can reach the framing, sheathing and insulation. Look for these signs:
- Water standing in the track after rain.
- Fogged glass between panes, which can mean water is pooling below the sash.
- Stains, peeling paint or soft spots on the sill, the trim or the wall below it.
- Flooring that lifts or swells near a sliding door.
- Musty smell or mold under a window. EPA says to bring in a pro for mold over about 10 square feet or if you suspect it's hidden in the wall.
- A slot that a previous owner sealed. The solution center suggests looking for caulk if you can't find the holes.
Go easy with a pressure washer near windows. The forensic report warns that a strong spray can push in more water than a weep hole can drain.
How to clean window weep holes yourself, and when to call a pro
Clearing slots is DIY for any window you can reach from the ground or from inside. Skip upper-floor exterior work if you'd need to lean out or climb, and do the track from indoors instead.
Call a window installer or a siding contractor if water still sits after you've cleaned the slot, if the frame is cracked or the sill slopes inward. Call one too if a patio, paver or deck has been built up against a sliding door. AAMA notes that brick, stone and pavers can block a door's drainage path. Stop and get a pro's opinion if you find wet insulation or soft wood. In a home built before 1978, don't scrape or sand old paint around the frame, because it may contain lead.
Weep hole covers are a cheap add-on for sliders. They're small flaps that keep bugs and dirt out, and a good one still drains. Check the fit after you put them in.
Weep holes in windows: your questions
Should I caulk window weep holes?
No. AAMA guidance says never to block them with sealant or anything else that stops water from draining. If a past owner caulked them, cut the caulk away.
Why is there water in my sliding door track?
Small amounts after rain can be normal while it drains. If it sits there, the weep slot is probably clogged, so vacuum the track and clear the slot.
Do all windows have weep holes?
No. Designs vary, and most swinging doors don't have them because their sills are solid. Your window maker's care sheet can tell you what yours has.
Sources: basc.pnnl.gov, warrenforensics.com, bdcnetwork.com, EPA
General guidance for U.S. homes, not professional advice. For gas, electrical and structural work, call a licensed pro.