How Does a Pressure Tank Work (Simple Explanation)

Last Updated on January 25, 2023 by Mattias

Do you have a pressure tank, or have you seen one but are curious about its role in pumping water to your home from your well?

In this article, you’ll learn what a pressure tank is, how it works, and how it collaborates with a well pump to supply water to your home. 

The knowledge of how a pressure tank works will also help you know how to tackle any issues that it might develop in the long run. 

How Does A Pressure Tank Work

green pressure tank for well

To properly understand how a pressure tank works, we must first look at a well pump and how it works together with a pressure tank to move water from the well to your home. 

After drilling a well and ensuring there is enough water in it, you need a medium that will move the water from its ground level to your home for your domestic use or other activities which you desire, and that is when a well pump comes in. 

Well pumps are built in different sizes and types to fit house sizes, water demand, and well depth, so ensure you consider these factors before choosing the right one for your home. 

Those whose water supply is city water enjoy the privilege of having the pressure of the water they use controlled by the city. However, if you use a well water system, you need to control the pressure of the water coming into your home by yourself, and that is when a pressure tank comes into the picture. 

A well water pressure tank also called a pressure storage tank, is a tank that is bestowed with the task of keeping the pressure in your water pipes and your entire plumbing system stable.

After the water is pushed out of the well pump, it sends it to the pressure tank to keep it under pressure until your plumbing fixtures need the water.

The ability of a well pressure tank to hold the water sent to it under pressure by the water pump is due to its use of compressed air pressure to cause an apt separation between air and water.

Whenever the faucet or any water-using appliance is used, the pressure tank knows it is time to send the water to your pipes and does so swiftly.

And after sending the water to these pipes, the tank fills up again but only when the pressure drops below the level previously set for it during the pressure settings process.

Note: The pressure tank is mainly set to compress air at 50 pounds PSI — Per Square Inch.

So, once a faucet or any water-using appliance has been used in your home, it reduces the pressure of your home’s water and alerts the water pump to push out more water from the well and send it to the pressure tank. 

Also, when the faucet or any water-using appliance used in your home is turned off, the pressure is replenished by the tank, and the pressure rises till it reaches a level at which the pump shuts off.

On the other hand, the pressure switch notifies the well pump when it is time to refill the tank.

When the pressure tank sends water to your water pipes to a particular volume, the pressure switch is triggered, and the well pump knows it is time to push more water into the tank. 

A pressure switch is usually set to stop when the difference between the pressure values reaches 20 PSI.

So, if you set your pressure switch to 50 PSI and the pressure in the tank drops to 30 PSI, the switch is triggered, and the well water pump is alerted that it is time to send water to the tank. 

The switch also alerts the well pump to turn off when the pressure value returns to its initial maximum pressure level of 50 PSI. 

There is also a pressure gauge attached to a pressure tank which measures the quantity of water sent to it when it gets filled and then decides if the tank should go off. 

Furthermore, note that the amount of water that can be pushed into your home’s water system per minute will determine the tank size you will use and the level of drawdown in your home. 

A Drawdown is the amount of water the pressure tank sends to your home from when the well pump goes off to when the well pump comes back up again. 

Tanks are in different sizes and can hold different gallons of water per minute, so ensure you confirm the volume of water your well system can pull per minute before choosing the perfect size for your home. 

However, if you have already gotten a well pressure tank and notice that the water pulled into your home per minute is more than it can handle, you should get a larger pressure tank.

Read also: How Fast Does Well Water Replenish? An Easy Explanation

Common Issues That Affect Pressure Tanks 

three red pressure tanks

• Your diaphragm could get blown if your pressure gauge shows that the pressure is below 10 PSI. 

• The top of the tank could feel filled or cold. This is an indication that something is wrong with your tank.

• Your well pump could turn on and off more frequently than usual, making it difficult for it to supply water to the pressure tank adequately 

The well pump is meant to turn on and off just once every 30 seconds, so if it does this more than once in that timeframe, or if its run time is shorter than specified in its manual, then you will know that there is a problem. 

You can use a stopwatch to measure the time length of your pump cycles.

However, for those with swallow wells that use a submersible pump, it might be hard to know if it is working, making it hard to measure its run time.

Nevertheless, if you are using any of the newer models of this electric pump, then you can use the relay switch light that it is built with to ease the stress of identifying whether it is active.

This problem is called short cycling, and it shouldn’t be taken likely, as it could shorten the life of your pump. 

• The pressure of your well water tank could become way less than its cut-in pressure even when all the water in it has been removed. 

If you notice any of these issues, you should endeavor to hire the services of a professional well inspector or contractor to check them properly for you and possibly resolve them.

Factors Which Can Shorten The Life Span Of Your Pressure Tank 

The expected lifespan of a pressure tank is 15 to 30 years, but certain factors can shorten its life span. 

These factors include the quality of water pushed to it from your well, the frequency of your pump’s cycling, the quality of the pressure tank, and how well it is maintained. 

• If your well has poor water quality, it could contain sediments like rocks and stone, which could cause holes in the tanks.

This is noticed more in diaphragm pressure tanks designed with diaphragm tanks than in other pressure tanks. 

• Quality pressure tanks are expected to last for 15 to 30 years and have at least a 5-year warranty, but if you purchase less-quality pressure tanks(which often cost lesser), you should expect them to last for 5 years.

• Carrying out pump cycling too frequently could also damage the rubber bladder in your pressure tank, especially in bladder pressure tanks.

• Negligence in the maintenance of your pressure tank could also shorten its lifespan, so ensure you check up on it from time to time and resolve any issue you notice immediately before it escalates.

Read also: 5 Ways To Reset A Well Pump Pressure Switch Without A Lever

How Does a Pressure Tank Work Summary

Hopefully, this article has answered all your questions concerning how a pressure tank works, everyday issues that could affect it, and factors that can shorten the life span of your pressure tank.