How to Drain a Water Pressure Tank

It is not uncommon for pressure tanks to become water-logged; even the best pressure tanks experience this problem. Having a waterlogged pressure tank is, however, a very serious issue.

Failure to resolve the problem could lead to more complicated teething troubles such as motor and pump operation failure. Therefore, you must be observant of the pressure tank to ensure it is running smoothly.

But how do I know if my pressure tank is waterlogged? Well, there are telltale signs that will indicate your pressure tank is having a water log problem.

Often you will hear the pressure switch producing some click sounds, meaning that the contacts are opening and closing at unwarranted rates. Also, when taking a shower, you may realize that water pressure fluctuates, increasing and decreasing at infrequent incidences.

The most common indicator of waterlogged pressure tanks is the pressure gauge reading needle jumping around. It shows that the pressure is not being properly regulated.

How to Drain a Water Pressure Tank

Having a waterlogged pressure tank could potentially burn out your pressure tank. You may want to call a professional to handle this problem as soon as possible however it is also a good idea you understand how to go about it.

Below are steps you can follow on how to drain a water pressure tank.

Step 1: Turn off the water pump switch

The first step to dealing with any broken electrical equipment is to ensure the power system is shut down. In most pumps, it is accomplished by turning off the switch or removing the fuse. You can also turn off the circuit breaker if the other options are faulty or not available.

Step 2: Open the shut-off valves

When you check the pipe between the water pump and house supply piping, there is a valve that you need to ensure is open. Often you will find it near the water pressure tank.

Step 3: Close the shut-off valve

You will find this valve between the water pump and the well pump. Close the shut-off valve to prevent the pump from losing prime. Don’t worry if your pump doesn’t have this valve, as it may not be available in some pumps.

Step 4: Drain the pressure tank

Before you open the drain valve, connect a hosepipe because you don’t want the water to spill all over your working area. More so, if the water has been there for too long, it could be contaminated with bacteria. Ensure the pipe attains some level of gravity because the pressure might not push the water uphill.

Once the pipe is in place, you can open the drain valve. Open a nearby tap such as the kitchen sink to allow air inflow into the system. Failure to do so, not all the water will drain.

How to Drain a Water Logged Pressure Tank

The first thing you will notice when your pressure tank is waterlogged is that the pump will run almost continuously or infrequently on and off. It causes excessive pressure to build up, which eventually leads to the pump burning out. You need to fix this problem as soon as possible because pumps are pretty expensive to replace. The following process will help you drain a waterlogged pump.

  1. First, you need to switch off the power supply to prevent injures such as electric shocks. Some pumps may lack a switch, so in such a case, turn off the circuit breaker or remove the switch. Connect the drain valve located at the bottom of the tank with a hosepipe and allow the water to flow out.
  2. Allow air into the tank by opening the tank valve or an outlet tap in the house. It also ensures that all the water in the pressure tank completely drains. Once complete, close the valve and check the pump’s pressure gauge to see if it meets the standard requirements. Locator the actuator on the pump and likewise check the readings to ensure they meet the required readings.
  3. If all the checks are in place, reconnect the power supply and check if the pump is running as required. You may need to reapply the pressure from time to time so that it remains within range. Run the water until it is clear, then return the other components such as the filtration process.

How to Fix a Waterlogged Galvanized Pressure Tank

A standard galvanized pressure tank is one of the oldest pressure tanks. This tank uses the same working principle, just like other tanks. Therefore in case, it becomes waterlogged, draining it is not any different. In a standard galvanized tank, water and air are always in direct contact. Given that water under high pressure absorbs a lot of air, the tanks become waterlogged after several months.

The first sign of a waterlogged galvanized pressure tank is that it will turn on and off after a few minutes. In severe cases, the pump will turn on and off after every second. You must drain the pump when it starts behaving this way because failure to do so may cause the pump to burn out.

Like most pumps, you need to first of all switch off the power to prevent electric shocks or short-circuiting the pump. Connect the drain valve with a hosepipe, direct it downhill, and then open the valve to allow the logged water to flow outside.

Ensure all the water is drained by opening a tap or the air valve on the tank. Once complete, add more air into the tank with an air compressor until it spurts from the drain valve. Use a   compressor to add pressure to the tank to about 3 to 5 psi below the pump cut-in pressure.

Check that everything is in place, then power on the pump. Allow the pump to run for a few minutes until the water is clear, then reattach the filtration process and any other components you were bypassing while draining the pump.


  1. Can a water pressure tank explode?

Yes. The pressure tank can explode when there is excessive pressure build-up in the tank. It happens when the tank has been around for too long that even with a valve present, the pressure still wears out the tank. You must check the pressure levels regularly to prevent such an occurrence.

  1. What causes the pump to lose pressure?

In most cases, it is usually a leak in the system. However, there are other reasons, such as an open tap in your house or a loose foot valve in the case of jet pumps.

What causes pressure tanks to get waterlogged?

The science behind waterlogged pressure tanks is that water under high pressure absorbs more air and other gases. It causes an imbalanced ratio between water and air, which makes the pressure fluctuate. Water, unlike air, cannot be compressed. The irregularities will cause the pump to go on and off, eventually damaging the motor.

Bottom Line

The pressure tank is an essential part of the water pumping system. It regulates water pressure and gives you access to water from the well without the need to manually turning it on and off.

However, the pumps face water log problems which are, of course, not unusual. But these problems are sometimes disastrous because they burn out your pump and even destroy the motor. You must take immediate action when the pump starts showing signs of being waterlogged.

Safety precautions