If your Arnold home runs on a private well, the pressure tank is the part of the system that keeps the pump from switching on and off every time someone opens a faucet. Most tanks hold pressurized air on one side and water on the other, and that air cushion pushes water to your taps. When the air is low, the tank fills with water, the pump cycles too often, and pressure at the house starts to act up. Checking the air charge is a reasonable homeowner task, but it involves electricity and pressurized water, so take it slowly.
Signs the air charge may be off
- The pump starts and stops in quick bursts, even when only a little water is being used.
- Water pressure at the taps rises and falls more than it used to, or the flow surges.
- When you press the air valve on top of the tank, water comes out instead of air, or nothing comes out at all.
- The pressure gauge needle swings widely while taps run.
Before you start
Read the label on the tank and note the pre-charge figure for the air side. Then look at the pressure switch and write down its cut-in and cut-out settings. Keep these numbers with your records. If the tank sits in a crawl space or damp utility room in an older Arnold house, look for leaks, rust, or corrosion around the fittings before you touch anything. If any step feels unclear, or if the tank is hard to reach, call a licensed well or plumbing professional rather than guessing.
Steps to check the air charge
- Turn off power to the pump at the breaker, then label the breaker so no one switches it back on during the check.
- Close the valve between the tank and the house system, if your setup has one.
- Open a tap inside the house, preferably a lower one, to relieve pressure in the lines.
- Attach a drain hose to the tank drain valve and open it. Let water drain until the flow turns to air, which means the tank is empty of water.
- With the tank empty and the tap still open, check the air valve with a tire-style gauge. Compare the reading with the pre-charge figure on the tank label.
- If the air is low, add air slowly with a hand pump or compressor, checking the gauge as you go. Stop when you reach the label figure, and do not overfill.
- Close the drain, open the valve to the house system, and let the tank refill. Turn the breaker back on, then watch the pump start and stop during normal use.
When the tank needs more than air
If the tank stays waterlogged after you add air, the internal bladder or diaphragm may have failed, and the tank may need replacement. If air leaks out again within a short time, check the valve core and fittings for leaks first. Frequent pump cycling after a fresh air charge can also point to a worn pressure switch or a leak somewhere in the house plumbing.
Keep the tank separate from water quality questions
A healthy pressure tank tells you about pressure and cycling, not about what is in the water. Well owners in south and west Jefferson County should handle lead questions as a separate job. EPA is actively addressing lead and heavy metals in private wells tied to the SW Jefferson County Mining Superfund area, so if your Arnold property is in that part of the county, sample the water itself for lead. Sediment and mineral deposits can also collect in the tank over time. When you drain it, note any grit, rust color, or odor, and mention those observations to whoever tests your water.
Keep a simple record
Write down the date, the pre-charge figure from the label, the reading you found, and any air you added. Repeating this once a year, or after any pump or tank service, makes it easier to see whether air is slowly leaking out. A short written history is also useful if you later need to explain the system's behavior to a technician.