Air only at upstairs faucets

Quick Answer:

If you see air spitting only from upstairs faucets, start by opening the affected tap fully and run it to purge the pocket of air. Test whether the spitting happens on hot water, cold water, or both. If the problem happens after a power or municipal outage, or after the water heater refills, it is often trapped air or a pressure/venting issue. If the air returns after purging or shows up across multiple fixtures or floors, a plumber should trace the supply and venting to find the source safely.

Why This Happens

• Trapped air in a short branch or in the water heater after a refill or restart can spit from an upstairs tap while lower fixtures flow normally.
• Pressure changes from outages, a water heater refill, or pump cycling can introduce air pockets into the higher parts of the system.
• Faulty mixing valves, a recently replaced valve, or incomplete flushing after work can let air reach fixtures. See Air spitting after installing new valve for similar scenarios.
• Pipes that rise and then run level can collect small air pockets that take time to clear; upstairs runs are more likely to trap air than short downstairs runs.

Step-by-Step What to Do

Step 1 — Open the faucet fully to purge air

• Turn the affected upstairs faucet fully on. Run it for a minute or more until the sputtering stops and flow becomes steady.
• If you have multiple nearby fixtures, open them in sequence starting from the closest to the main riser to help push the air out.

Step 2 — Test hot-only vs cold-only

• Shut off the cold handle and run the hot only; note whether spitting appears. Then run cold only. This tells you whether the air is coming from the water heater or from the main supply side.
• If it happens only on hot, suspect the heater or its connections; if only on cold, suspect municipal supply side or a local branch line.

Step 3 — Note timing with outages and heater refills

• If the spitting started right after a power outage, a pump restart, or when the water heater refilled, it’s likely trapped air that can clear with purging.
• Keep a record: does it happen immediately after these events, or randomly? Repeating after the same event suggests a venting or refill path issue.

Step 4 — Compare upstairs to downstairs behavior

• Run a downstairs faucet at the same time. If downstairs is steady while upstairs sputters, the problem is likely localized to the upstairs branch, riser, or heater-related plumbing.
• If multiple floors show spitting, the issue is less likely to be a single upstairs branch and more likely supply pressure, main vents, or a component that serves the whole house. See notes about winter work: Air spits after winterization.

What Not to Do

• Don’t keep cycling the main shutoff valve to “fix” air—this can introduce more turbulence and make pockets worse.
• Don’t start dismantling cartridges, complex mixing valves, or faucet internals unless you are experienced; you can create leaks or contaminate the system.
• Don’t assume a permanent fix after a single purge if the air returns. If air returns after purging or affects multiple floors, let a plumber inspect venting and supply components rather than chasing it yourself.

When to Call a Professional

• If the sputtering continues after you purge and test hot vs cold, call a plumber to trace the riser, mixing valves, and water-heater connections.
• If air affects multiple fixtures or floors, a plumber should check supply pressure, check valves, and any mechanical vents or pump controls.
• If you notice pressure loss, banging, persistent sputtering, or signs of leaks while troubleshooting, stop and get professional help.

Safety Notes

• Avoid turning tools or using open flame near plumbing; water heater components and plumbing can have electrical parts or combustible areas.
• When running hot water to test the heater, be cautious of scalding — run cold first or mix to a safe temperature before prolonged checks.
• If you shut off the main or work near electrical panels or pumps, switch things off safely and follow manufacturer guidance; when unsure, stop and call a pro.

Common Homeowner Questions

• Q: Is air spitting dangerous?
  A: Not usually dangerous, but it can indicate pressure or venting issues that a plumber should review if persistent.
• Q: Will I need new pipes?
  A: Most times no; trapped air, the water heater, or a local valve are common causes and are fixable without replacing piping.
• Q: Can I fix this myself?
  A: Try the purge and hot/cold tests first; if it returns or affects many fixtures, call a plumber rather than dismantling parts yourself.

For more related articles, see the Air Spitting From Faucets hub.