Quick Answer:
If air only appears on the first use after the house sits empty for a while, run one cold faucet briefly. If the sputter clears fast and doesn’t return, it’s most likely dissolved air coming out of solution and not a serious leak. If bubbles keep showing up every time you use the water even with regular use, the problem may be air entering the system or a failing valve and needs further checks.
Why This Happens
Water can hold dissolved gases. When a plumbing system is unused for days or weeks the gases can come out of solution and form tiny bubbles. Those bubbles travel through pipes and show up as sputtering at the first faucet you open. Other causes after a long vacancy include recent work on the supply (meter or shutoff activity), a partially closed valve, or a leak on a pressurized feed that allows air in.
Step-by-Step What to Do
Step 1: Confirm the pattern
- Check that the sputtering happens only on the first use after the house sits unused. Try faucets at different fixtures after a long idle period.
- Note whether the problem is on cold, hot, or both. Cold-only sputter points to supply-side air; hot-only suggests the water heater or hot-side plumbing.
Step 2: Run one cold faucet briefly
- Open a cold faucet for 10–30 seconds. If air clears fast and doesn’t return during later uses, it’s likely dissolved air releasing and the system will behave normally with use.
Step 3: Test frequency
- Use faucets normally for a day or two. If bubbles reappear only after long idle periods, you have the common “first-use” air behavior. If bubbles appear every time, even with frequent use, it may suggest air entry or a failing valve and you should move to the next checks.
Step 4: Check recent work and valves
- Ask whether the water utility or a contractor worked on the meter or the main shutoff while the house was empty; work can introduce air. For these situations see Air trapped after meter replacement and Air sputters after main shutoff used for specific troubleshooting steps.
- Ensure the main shutoff and any isolation valves are fully open and not partly closed.
Step 5: Look for ongoing air entry
- If air comes back during normal use, inspect visible fittings, hose bibs and any pressure-reducing valve for signs of leaks that could admit air. For well systems, check the pump and pressure tank for air-related issues.
What Not to Do
- Don’t assume it’s dangerous contamination if bubbles clear quickly — that pattern is usually harmless dissolved air.
- Don’t dismiss persistent cloudiness, discoloration, or a sour/chemical odor — those can indicate contamination and need attention.
- Don’t force or hammer on buried or pressurized components; avoid unsafe DIY attempts on the main supply if you’re unsure.
When to Call a Professional
- If the sputtering returns every time even with frequent use, call a plumber — ongoing air entry or a failing valve often needs diagnosis and repair.
- If you notice cloudy water that doesn’t clear, visible discoloration, or a bad smell, contact your water supplier or a pro before drinking or cooking with the water.
- If the issue follows recent utility work and doesn’t clear after running fixtures, ask the utility or a plumber to inspect for trapped air or service-side issues.
Safety Notes
- If water is cloudy with an unusual color or odor, do not drink it until the source is confirmed safe. Contact your water utility or a plumber for testing and guidance.
- When running faucets to purge air, open only one fixture at a time and avoid allowing water to splash; be careful with slippery surfaces from runoff.
- Turn off the main and call a plumber if you see worsening leaks or if valves appear damaged. Don’t attempt complex repairs on pressurized components unless you are trained.
Common Homeowner Questions
- Q: Is this dangerous? A: Usually not if bubbles clear quickly; persistent cloudiness or bad odors are the concern and should be checked.
- Q: Will regular use prevent it? A: Frequent use usually prevents dissolved-air buildup. If the problem returns despite regular use, have the system inspected.
- Q: Could the water heater cause it? A: Yes — if only hot water sputters after a long idle period, the heater or its fittings may be releasing trapped air and should be checked.
Related Articles
If you’re troubleshooting a similar symptom, these guides may help:
For the full directory, see Air in Pipes After Shutoff.