Yesterday while filling a large container from a garden hose I noticed that periodically some air bubbles would emerge from the hose.

The hose is plumbed into a tee close to the main water supply in the basement - which is from our well pump. Down in the basement I could hear the bubbles proceeding through the pipe. It seemed that pretty much they would occur whenever the pressure switch turned the well pump on.

All the pipework from main supply line to the hose is visible - I couldn't detect any leaks at all. So its not like air is entering that line somewhere.

I have no idea how long this has been going on. I only noticed as mentioned because I was observing the hose for a while filling a large container, but doing this is out of the ordinary.

I can think of these possibilities:

  1. Well running dry. Except that it hasn't: water is plentiful. It has never run dry in the past. (~9 years in this house)

  2. Leaky underground pipe in between the pump and the house. Pump stops, some air creeps in; pump starts up, pushes air out. The pipe is galvanized steel where it comes through the wall, not sure of its composition anywhere else. But if its original (from 1973) galvanized all the way seems likely?

There could obviously be something I'm not thinking of. Any tips on how to diagnose this? At least to narrow it down?

  • Hopefully, not water from the garden hose reentering the plumbing when pressure drops! Commented Aug 31, 2020 at 21:39
  • @DrMoishe Pippik I don't think that is possible, the end of the hose was fully submerged the entire time. Also we could hear the air migrating along the pipes in a single consistent direction. And also the water flow never stopped. Commented Aug 31, 2020 at 21:45
  • Just a guess, is the level of water in the pressure tank running low-to-empty before the pressure switch cycles on the pump. Have you tried adjusting the pressure switch to see if will cycle on before the pressure tank is depleted to much?
    – Alaska Man
    Commented Sep 1, 2020 at 0:59
  • Do you have a jet pump or submersible? I have seen jet pumps suck air at the pump prior to failing.
    – Ed Beal
    Commented Sep 1, 2020 at 8:05
  • @EdBeal I have never had to inspect or replace the pump before, so that is hard to say. We don't know how deep the well is either. It is a 240V 30A pump circuit if that's any clue. Commented Sep 1, 2020 at 13:52

1 Answer 1


My guess would be the line above the pump may be cracked on a submersible a check valve keeps the water in the tank but at the crack the water drains back and when the well kicks in water pushes the air into the tank.

A submersible will only have power and 1 line going down the well head.

Pulling a pump is not really that hard but one thing most don’t tend to do.

Before starting fill a clean trash can with water (I actually use a 55 gallon food grade barrel now but a clean trash can will work) very clean no trash bag that will block the pump from drawing the water.

I usually cut the pipe where I Can splice it if plastic if metal there is usually a union. The Well cap may be an expanding type or just have a rubber seal usually 2 plates screwed together. Turn the power off Pry the cap up then start pulling, there may be enough wire so it doesn’t need to be cut but if it has to be cut it’s not hard to repair. Pull the line up you may see the crack when pulling up if not I use a clean trash can described above place the pump in the can filled with water. Cap the pipe where it was cut and turn the power on it should only take a few seconds to pressurize the line and show the leak don’t leave it on for long or the pump will overheat. This is usually where I find the leak and quite often because a torque arrestor was not used. the pump jumps every start and eventually cracks the poly line. If you have metal it’s time to upgrade to poly.

I don’t think it is the pressure tank because you said it was with each start cycle.

  • I had similar case - pipe with pump joint got loose due to submersible pump rotating a little with every start. This led to water between pump and check valve to run out and be replaced with air that got pushed up to tank as soon as pump started. This had specific sound/effect of air coming through pipes right before pump started. Commented Aug 4, 2021 at 20:43

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