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This article describes How to Repair or Replace Leaky Water Tank Air Valves or Schrader Valves which are used for adding air to a water pressure tank such as the water tank air valve. Readers of this document should also see Water pump and pressure tank repair diagnosis & cost an specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost.

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How to Fix a Leak at the Water Tank Air Charging Valve

Sometimes when we remove the cap from a water tank air valve, or more likely when we try pumping air into the water tank at the water tank's air valve, we're troubled by water (or air) leaking back out at us from the valve - making us sorry we touched it in the first place.

If the air valve or "tire valve" or Schrader valve on your water tank is leaking water or air there are a few wonderfully easy steps you can take.

We describe how to clean an air valve on a water tank to get it to stop leaking (water or air), how to make a simple emergency repair to force it to stop leaking, and how to replace a leaky valve stem core in a water tank air valve.

Step 1: Clear dirt on the valve stem internal parts on the water tank air valve:

The little tip that you see showing in the center of the water tank air valve stem is the part of the valve stem core that is depressed to open the air valve and permit air into the water pressure tank when you connect a tire pump or a can of compressed air.

Try just gently depressing the little pin exposed in the center of the valve stem. This pushes down a spring-loaded valve-stem core part that will let water or air flow OUT of the valve. Basically you are opening the valve.

You can use a pen tip or any small instrument. Here we're using a dental pick from our forensic lab but any small item that won't itself break off in the valve should work.

Don't bend or force the pin as you don't want to make things worse. Often by flushing out the seat of the valve stem core in this matter you'll remove some debris that was keeping the valve from closing fully in the first place - it may be the only repair step you need to stop leaks at a water tank air valve.

If your water tank is a "captive air" or bladder type tank you should feel air coming out of this valve when it's opened, but not water. If water comes out the water tank's bladder is ruptured and the tank bladder or whole tank need replacement.

If your water tank is not a type that uses an internal bladder to keep water and air separated, OR if the air valve is located not on the water tank itself but at a plumbing fitting near the bottom of the water tank, you may find some water coming out of this valve. That's ok for now. For an air valve located on top of any water tank, when the tank has been properly air-charged (See WATER TANK AIR, HOW TO ADD) you should not see water coming out at the air valve.

Step 2: How to install a cap to stop a leaky water tank air valve: Just screw on a valve stem cap tightly.

If your water tank's air valve is leaking and there is no valve cap, run out your car and borrow a cap off of one of your tires or off of a nearby bicycle or motorcycle (you can replace the borrowed valve stem cap later today.)

Screw the cap tightly onto the air valve stem at your water tank.

This will usually stop any water leak and will slow way down an air leak at the water pressure tank's air inlet valve.

Step 3: Get the necessary parts and tool to replace a leaky water tank air valve: At your nearest auto parts supply store you can pick up the following inexpensive items you'll need to replace a leaky air valve on a water tank. Our photo shows from bottom left moving clockwise:

• A valve stem core removal/replacement tool - this is a little tool that will let you unscrew the old valve stem core and screw in a new one. Buy a good tool - it's still cheap and the better tool is more likely to be able to extract an old crusty valve stem core.
• A new valve stem core - (we show two types in this photo). This is a tiny valve part that screws into the center of your air valve stem. You'll want the short type valve stem core since it's most likely to fit your water tank without a problem. The diameter and threads will be standard on all U.S. made water tanks and similar equipment using a Schrader valve design. Some bicycle tires and tires in other countries use a metric diameter and metric threaded valve stem and valve stem core which won't fit a U.S. made water tank air valve.
• A new water tank air valve cap - this is just a tire valve stem cap. Plastic doesn't corrode, metal is stronger and probably seals better. In our photo we show both a black plastic valve stem cap and a metal valve stem cap. The metal tire valve cap at bottom center in our photo includes a handy feature - it can also be used as a tool to screw a valve stem core in or out.
  
  

Step 4: Replace the leaky water tank air valve core, using the parts at the step above and by following these simple steps:

• Turn off the water pump at its electrical switch
• Remove water pressure from the water tank by running water in the building until the tank pressure gauge is close to or at zero - you don't have to empty the water tank, just get most of the pressure off so you're not going to be squirted with water or air when you repair the valve
• Use the air valve stem core replacement tool and parts described above remove the valve stem cap and then to unscrew the old valve stem core and screw in the new one. If you can't get the valve stem cap off it's OK to use a small pair of pliers to gently unscrew the cap (counterclockwise to loosen the cap). If you can't unscrew the old valve stem core, try placing one drop of Liquid Wrench or a similar product into the valve stem on the threads that surround the core. Don't use excessive force - cross-threading the valve stem means the new core may not seal well and you'll be back to the emergency repair of just installing a tire valve cap on the valve stem.
• Close any plumbing fixtures you opened to take pressure off of the water tank
• Turn the water pump back on and let it re-pressurize the water tank

Step 4 alternative: replace the entire leaky water tank valve assembly.

It is also possible to replace the entire Schrader Valve assembly. If your old valve is badly damaged or leaks at its base where the valve screws into the water piping, or if you can't just screw in a new valve core this is what you'll need to do. In our photo above our pliers are loosening the black plastic valve stem cap.

Schrader valves whose body bottom is threaded and are screwed into a water tank or water pipe can be replaced entirely. Schrader valves that are welded to the top of a water tank cannot be replaced - just their valve stem core.

But alternatively you could use a small wrench to unscrew and replace the entire valve assembly Notice the white teflon tape we wrapped around the threaded part of the water tank air bleed valve assembly when we installed it in the first place. As we described above, you'll need to remove water pressure from the system to make a complete valve assembly replacement. First be sure you have on hand, in addition to the tools described above:

• Tool to loosen and then reinstall the valve assembly - it's a screw-in part.
• Pipe dope or teflon tape to seal the threads on the water tank air new valve assembly
• A new replacement water tank air valve - be sure the diameter of the threaded portion of your new valve matches the threads on the old one.
  
  

Step 5: Check for leaks at the water tank air valve - chances are very good that the air valve is no longer leaking. If it is still leaking you may be able to remove the stem core, clean the valve threads, and try again. If that doesn't work you need a new water tank or a plumber who can change the entire valve assembly (unlikely).

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

PLUMBING TOPICS
APPLIANCE EFFICIENCY RATINGS
OIL TANKS
SEPTIC SYSTEMS
WATER PRESSURE REGULATOR ADJUST
WATER PRESSURE REPAIR GUIDE & COSTS
WATER PRESSURE LOSS DIAGNOSIS GUIDE
WATER PRESSURE & FLOW MEASUREMENT
  WATER PUMP PRESSURE CONTROL ADJUSTMENT
  WATER PUMP PRESSURE CONTROL REPAIR
  WATER PRESSURE REGULATOR ADJUST
WATER PUMPS & WELL TANKS
WATER PUMP CONTROLS & SWITCHES
  IDENTIFY WELL PUMP TANK COMPONENTS
  MAIN WATER SHUTOFF VALVE
  WATER PUMP ELECTRICAL SWITCHES
  WATER PUMP PRESSURE CONTROL
    WATER PUMP PRESSURE CONTROL ADJUSTMENT
    WATER PUMP PRESSURE CONTROL REPAIR
    WATER PUMP PRESSURE CONTROL REPLACE
  WATER PRESSURE REGULATOR ADJUST
  WATER PUMP RELAY SWITCH
  WATER TANK AIR VOLUME CONTROLS
  TANK AIR INLET VALVE
  TANK AIR VALVE REPAIRS
  WATER TANK PRESSURE GAUGE
  WATER PRESSURE GAUGE ACCURACY
  WATER TANK DRAIN VALVE
  WATER TANK RELIEF VALVE
  CHECK VALVES
  WATER FILTERS
  WATER FILTERS
WATER PUMP SHORT CYCLING
WATER PUMP TYPES & LIFE EXPECTANCY
WATER PUMP & TANK SAFETY
WATER SHUTOFF VALVE LOCATION, USE
WATER SOURCE ALTERNATIVES
WATER SUPPLY & DRAIN PIPING
WATER TANK TYPES: WATER, OIL, EXPANSION, ALL
WATER TANK LIFE EXPECTANCY
WATER TANK REPAIRS
WATER TANK AIR, HOW TO ADD
WATER TANK BLADDERS & CAPTIVE AIR
WATER TANK BLADDER PRESSURE ADJUSTMENT
WATER TANK PRESSURE CALCULATIONS
WATER TANK PRESSURE GAUGE
WATER TANK SIZE & VOLUME
WATER TANKS HOW THEY WORK
WATER TESTING
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL, PUMP, TANK LIFE EXPECTANCY

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