Quick Answer:

Most often the leak appears only with a hose attached because added backpressure or a poor seal at the hose connection reveals a damaged washer, worn spigot seat, cracked vacuum breaker, or a defective hose-end check. Start by removing the hose and testing the spigot bare, then inspect the vacuum breaker for cracks. Many fixes are simple (replace a rubber washer or vacuum breaker); if the spigot still leaks without a hose, call a plumber.

Why This Happens

• When a hose is attached it changes the pressure and how water flows at the spigot. A small defect that doesn’t leak when water runs freely can leak under the extra resistance of a hose.
• Common parts that fail under hose pressure are the hose washer, spigot seat or packing, and the vacuum breaker. A cracked vacuum breaker often leaks only when the hose is connected because water is forced through the damaged area.
• Sometimes the hose itself has a built-in check valve or damaged end that forces water back into the spigot connection and causes a leak.
• If the spigot works normally when bare but leaks with a hose, the problem is usually at the connection point rather than the main shutoff.

Step-by-Step What to Do

1. Remove the hose and test the spigot bare

• Turn the spigot fully off, then remove the hose by hand.
• Turn the spigot on briefly and watch for leaks. If you see water dripping from the spigot outlet or around the valve stem with no hose attached, the spigot itself needs repair.
• If the spigot is dry without the hose, the problem is likely the hose or the connection seal.

2. Inspect the vacuum breaker for cracks

• Look at the small attachment near the spigot outlet (the vacuum breaker or backflow preventer). Check for visible cracks, loose parts, or mineral buildup.
• Gently wiggle the vacuum breaker to see if it is hard-mounted or damaged. A cracked vacuum breaker can leak only when pressure changes with a hose attached.
• If it’s cracked or warped, plan to replace it. Replacements are inexpensive and simple to swap out.

3. Check the hose and connector

• Inspect the hose end washer and the hose coupling for damage or debris. A flattened or missing rubber washer will not seal under pressure.
• Try a different hose or attach the hose to another spigot to see if the leak follows the hose.
• Hand-thread the hose on and stop once it is snug; avoid tools that could deform the connector.

4. Inspect and replace small spigot parts if needed

• If the spigot leaks without the hose, replace the internal washer, seat, or packing nut. These are common wear parts and often fix the issue.
• For threaded spigots, check the male threads for cracks or corrosion that prevent a tight seal.
• If you’re comfortable, shut the water off at the outdoor shutoff or main before replacing parts. If not, call a plumber (see below).

5. Reattach the hose carefully and retest

• Attach the hose by hand until snug and turn the spigot on slowly.
• Watch for leaks at the connection and around the vacuum breaker. If the leak returns, replace the suspect part (hose washer, vacuum breaker, or spigot cartridge).

For related issues, you may also want to check Outdoor Spigot Has No Water After Winter or read about Outdoor Spigot Won’t Turn Off Completely.

What Not to Do

• Do not overtighten hose or ignore cracked vacuum breakers.
• Do not use excessive force on frozen or stiff spigots — that can break the valve.
• Do not assume the hose is fine without inspecting the washer and coupling; a damaged hose end often causes the problem.

When to Call a Professional

• If the spigot leaks without any hose attached after you’ve checked washers and the vacuum breaker.
• If replacing obvious parts doesn’t stop the leak, or if you find corrosion or internal valve damage.
• If you’re unsure how to shut off the water safely, or if the spigot is frozen and leaking when it thaws — a plumber can prevent further damage.
• If there is water damage inside the wall or you see persistent low pressure when a hose is attached, get a pro involved.

Safety Notes

• Turn off the water supply before replacing internal spigot parts. Release residual pressure by opening the spigot after shutoff.
• Wear gloves and eye protection when working on corroded metal to avoid cuts and debris in your eyes.
• Avoid using flame or improvised heat to thaw frozen spigots — use safe thawing methods or call a professional.

Common Homeowner Questions

• Why does the spigot leak only with the hose attached? Because the hose changes pressure and exposes a poor seal, damaged washer, or cracked vacuum breaker.
• Can I fix this myself? Often yes — replacing a hose washer or vacuum breaker is simple; replace internal parts only if you can shut off the water.
• How urgent is this? If the leak is small and confined, you can troubleshoot; if water is seeping into walls or creating damage, call a plumber right away.