Why Are My French Doors Leaking? Causes and Easy Fixes

Troubleshooting · 3 min read · Updated October 2026

French doors usually leak because the weatherstripping has worn out, the threshold has drifted out of line with the door bottom, or the weep holes are blocked. A hose test shows which one in a few minutes.

Find the path before you buy anything. Water follows the easiest route, and it is often not where the stain is.

Find the leak in three steps: look for daylight around the frame, dollar bill test on the seal, hose test from the bottom up with a helper inside — Do them in this order. Source: Doors and Beyond, October 2025.

Table of Contents

Finding where it comes in

Doors and Beyond suggests a daylight check first: turn off the interior lights on a sunny day and look for light through the frame.

Then slide a dollar bill into the seal, close the door and pull. If it comes out easily, the weatherstripping is done.

For the water test, have a helper inside and spray the door with a hose from the bottom up, a few minutes per section. Starting low keeps you from soaking the spot you are about to test.

Raindrops on a glass door — Wind-driven rain finds gaps that calm rain misses. Photo: Valeriia Miller on Pexels.

Common causes

The Doors and Beyond list covers failed weatherstripping, blocked weep holes, a sagging hinge that leaves uneven gaps, cracked caulk at the jambs and gaps where the frame corners separate. It also lists water pooling at the threshold because of poor drainage.

The same page says weatherstripping lasts 5 to 7 years, or 3 to 4 in harsh climates. Treat that as one retailer’s estimate.

Common French door leak causes: worn weatherstripping, blocked weep holes, threshold out of line with the door, sagging hinges, cracked exterior caulk, water pooling at the threshold — Check the cheap ones first. Sources: Doors and Beyond, HouseCalls.

A threshold problem is easy to miss. In a repair shown by HouseCalls, the threshold ridge sat almost an inch out of line with the door bottom, so rain ran over the drip cap and inside.

Fixes you can do

Clear the weep holes first, because it costs nothing. Then replace worn weatherstripping and add a door sweep.

Re-caulk the jambs with an exterior-rated polyurethane or silicone. If the door sags, swap short hinge screws for longer ones, about 3 inches, that reach the framing.

For the door bottom, HouseCalls chose one with a rain diverter and a vinyl gasket, leaving about a half-inch gap above the threshold. Hose-test again when you finish.

My call · George Anderson

I would do the hose test before buying anything. Replacing weatherstripping will not fix a threshold that sits an inch off, and you will have paid for the wrong repair.

When to call a pro

Call one for rot, signs of insect damage or movement in the frame, or water that has reached the walls. Also call if the warranty requires professional repair.

Doors and Beyond puts DIY materials at $105 to $255 and a professional threshold repair at $400 to $600. Prices vary a lot by region, so get a quote.