Quick Answer:
You notice air spitting from the kitchen tap and worry the system is drawing air or losing pressure. First, open the faucet fully to purge any trapped air and test hot-only versus cold-only to locate the source. If the problem repeats across other fixtures or after a refill or outage, a plumber can trace the issue safely.
Why This Happens
Small pockets of air can get into the supply line and come out as sputtering or spitting at the faucet. Common causes include:
- Recent shutoffs or pressure changes from the utility.
- Work on your plumbing or nearby mains that introduced air into the lines.
- Water heater refills or changes in heater pressure that push air into the cold or hot side.
- Trapped air after winterization or after refilling appliances.
If only one fixture shows the problem, the trapped air is likely local to that branch. If multiple fixtures or floors show spitting, the source is higher up the supply chain or in a system component such as venting, the main supply, or the water heater.
Step-by-Step What to Do
1. Open the kitchen faucet fully to purge air
- Turn the tap to full flow (both hot and cold if it’s a mixer) and let it run for 30–60 seconds. That often pushes pockets of air out of the line.
- If the sputtering stops, run the tap a little longer to make sure the line is clear.
2. Test hot-only versus cold-only
- First open only cold water and observe. Then close it and open only hot water. Note which side sputters.
- If only one side spits, the problem is likely on that branch (for example, the water heater or a local valve). If both spit, the air is likely upstream.
3. Note recent events: outages, refills, or winter work
- Did this start after a power or supply outage, or after servicing the heater? Air often appears after those events.
- If you winterized or recently restored lines, check the guidance specific to winter work — see Air spits after winterization for common follow-ups.
- If the issue followed a water heater refill, review steps for heater-related air issues such as Air spurting after water heater refill.
4. Compare upstairs versus downstairs and other fixtures
- Open a bathroom sink or shower on the same floor, then a fixture on the floor above or below. Note any pattern — only the kitchen, only downstairs, or multiple floors.
- Patterns help determine whether the trapped air is in a local branch or the main supply.
5. If air returns after purging, watch and document
- Run the tap again and note how long the sputtering returns and whether it follows any activity (like the heater cycling or other fixtures being used).
- Take notes or a short video of the behavior and when it occurs — this helps a plumber diagnose the root cause faster.
What Not to Do
- Don’t keep cycling the main shutoff valve trying to clear air — that can introduce more turbulence and make the problem intermittent.
- Don’t dismantle faucet cartridges, valves, or other components unless you are trained — that risks damage and leaks.
- If air returns after purging or affects multiple floors, let a plumber inspect venting and supply components rather than attempting further DIY fixes.
When to Call a Professional
- The sputtering won’t stop after purging and testing hot vs cold.
- Air appears in multiple fixtures or on multiple floors.
- You notice pressure loss, water hammer, or frequent air that follows the water heater cycling or utility work.
- You’re unsure where the supply components or venting are located or comfortable inspecting them — a plumber can trace the source safely.
Safety Notes
- Watch for scalding when testing the hot side. Start with cold first, and be ready to turn hot off quickly.
- Do not turn the gas or electrical supply to a water heater on or off as part of this test unless you know the correct safe procedures.
- If a leak appears while running fixtures, turn off the supply to that fixture and call a plumber.
Common Homeowner Questions
- Why does only one faucet spit air? — Local air pockets or a valve on that branch are most likely.
- Will running all faucets clear the air? — Often yes for a single event; persistent or recurring air needs inspection.
- Can the water heater cause air in cold lines? — Yes—refills, pressure changes, or trapped air in the heater can push air into piping.
For more related articles, see the Air Spitting From Faucets hub.