Why Is My Hot Water Tank Constantly Filling?

Water heaters are prone to faults and repairs like any other home appliance. Most of the time, fixing the issues with the water heater is quite easy, and you can do it yourself. However, some complicated issues need professionals’ assistance.

Your hot water tank may constantly be filling due to leaks in the drain valve. You will need to replace the drain valve to fix this. Another reason may be high pressure due to high temperatures. You’ll need to adjust the water pressure by locating the regulator and using a wrench to turn the bolt.

In this article, I will help you understand the possible causes behind your hot water tank constantly filling. I will also share proper maintenance tips, so this doesn’t happen again. So, keep reading.

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What causes a water heater to keep running?

If your water heater is continuously running, it should not be taken lightly.

It indicates that something is wrong with it.

You must take immediate actions to fix this issue before it leads to bigger problems.

Before taking action, you need to know the root cause of this problem. 

I faced this issue 2 months ago, and after my research and inspection, I learned some of the common causes of why the water heater keeps running.

There can be various reasons, not just one. So I will share them all.

1. Sediment deposition

Every time the water heater heats, minerals like magnesium and calcium in the water deposit at the bottom of the heater tank.

This is called sedimentation.

Someone who flushes or cleans the tank regularly won’t face this issue.

Sedimentation occurs if you haven’t cleaned the tank in a long time. 

When deposition keeps occurring, cracks develop over the sedimented mineral particles.

Through these cracks, water starts to leak. 

Not only leakage, but it also causes other issues.

It decreases the water heater’s effectiveness by blocking the heating element from reaching the water.

If this happens, the water doesn’t stay as warm as it should. 

As a result, your water heater takes extra time to run the water, raising your gas or electric bills.

Also, when the steam protrudes from the sediment to heat the water, the deposited materials will start floating around the tank’s inner lining, damaging the lining and affecting the steel material found on the bottom. 

Above all, sedimentation will contaminate the water by rusting the pipelines in the long run.

When these rust materials are mixed with water pipelines, they contaminate the water. 

It’s dangerous to consume this contaminated water.

2. Old water tanks

If you find hot water from the water heater is yellowish, the tank has exceeded its average period of 10 to 12 years. 

When your water heater is too old, even after changing the thermostat, there will be issues regulating the temperature. 

You can confirm this by checking the manufacture date of the heater.

If you use your water heater tank for many years, part of the water heater gets damaged in the long run. 

Rusting of internal parts also happens, which leads to corrosion. 

In this case, water leaks frequently. 

Replacement of the water heater is the only solution.

3. Drain valve fault

Drain valves drain the water from the heater while cleaning and for maintenance.

While doing this, the drain valve may be loosened in the long run, allowing the water to leak.

If this is the cause of the constantly running water heater, replace them immediately.

The constant running of water will flood the area and damage the floor and the wall.

Follow these step-by-step processes to replace the drain valve:

  • Drain the water. 
  • Turn off the electricity if you have an electric water heater or the gas if you have a gas water heater.
  • Locate the water supply wall and turn off the water supply. 
  • Next, disconnect the hose.
  • Then use a wrench to remove the old drain valve by turning it in the counterclockwise direction. 
  • Install the new drain valve. Wrap the edge with the tape, and use a wrench to tighten it in the clockwise direction. Don’t stop until the drain valve is fixed tight.
  • Now it’s time to fill it with water. Check if your water heater is filled by opening the hot water faucets.
  • Turn on the gas or electricity. Finally, check for any leaks. As you have installed a new drain valve, your water heater must not leak. 
  • If you find replacing the drain valve complicated, consider hiring a professional.

4. Excess pressure

It is common for a plumbing system to create pressure.

As the water is heated inside a heater, steam is created. 

The pressure inside the water heater becomes high because there is no way for the steam to escape.

The water starts to leak to reduce the pressure inside the water heater.

This usually happens when the heater’s temperature is way higher than required. 

It also occurs due to the high pressure of water entering the water heater. 

You can adjust the pressure of water by following these steps:

  • Start adjusting the water pressure by turning off the valve of the water supply.
  • Locate the water pressure regulator with the bolt to adjust the pressure. Use a wrench to turn the bolt counterclockwise to decrease the water pressure and clockwise to increase the pressure. Keep the pressure between 40 and 60 PSI.
  • After making the necessary adjustments, lock the bolt by using the wrench.
  • Now you can turn on the water supply. Check the pressure of the water, and if the pressure is not adjusted even after doing this, you need to replace the pressure regulator.

5. Damaged storage tank

See if there is an additional water heater to store excess water. 

Some water heaters have these types of tanks, while many don’t.

If your water heater has this storage tank, it may also be the reason for the leakage. 

These storage tanks have a glass lining inside them.

After long usage, there will be mineral deposition on the glass.

Due to this, the glass will start to produce cracks, leading to water leakage. 

In this case, you have to replace the storage tank.

If your water heater doesn’t have this type of tank, skip this step. 

6. Corrosion of anode rod

The purpose of an anode rod is to attract rust and corrosive materials to prevent the interior body of the water heater from getting corrosive. 

It keeps the water heater safe from rusting elements. 

The issue will arise when the anode rod becomes fully damaged due to the accumulation of corrosive materials.

Leakage happens in the place where an anode rod was initially present. 

Replace the anode rod to solve this leaking issue. 

Hiring a professional to replace the anode rod is recommended because it requires technical knowledge and experience.

7. Internal tank leakage

The internal tank is a complicated issue you cannot sense outside the water heater. 

It has two shells where the interior tank holds the water to give you a basic understanding of how the water heater is structured.

The exterior layer of the shell passes the insulation to the interior, where both shells are covered with a metal layer.

It is hard to fix when leakage happens in the interior tank, which holds the water.

It would be best to hire a professional if you are not aware of the technical side of plumbing.

In this case, you can take action as per your technician’s advice.

How do I stop my water heater from filling up?

It is possible to stop your water heater’s leakage by following the five steps mentioned below.

However, complicated issues require professional assistance.

1. Fix the leaks

Leakages are the most common issue that causes the water heater to fill up.

Check the heater’s sides to find where the leakage is happening.

You can easily fix it by replacing the part or tightening it with the wrench.

2. Check the pressure valve

As discussed above, you should inspect the pressure valve for any faults. 

It is crucial to regulate the pressure and temperature of the water inside the water heater. 

You can find the valve at the top of the water heater.

Check if there is leakage, and fix it using the wrench

Sometimes just by tightening the valve, you can solve the leakage issue. 

Or else you have to replace it. 

Fix the water pipe leaks:

  • Check for water leakage in the pipes, bringing water in and out of the water heater. If there is any leakage, fix it by replacing the pipes. Or try to tighten it with the wrench instead of trying to wrap the tape in the damaged area.
  • If there is leakage in the pipes, it will disrupt the regular functioning of the water heater, leaving it to work overtime.
  • Seek the help of a professional to do this job if you aren’t experienced at doing this work.

3. Install the water heater insulation

Insulation in your water heater will maintain the temperature of the water. 

Doing this will prevent the water heater from frequently running to keep up the temperature of the water.

Sometimes, heater insulation will be at fault, which is why your water heater is constantly filling.

It’s easy to fix this issue.

You must add extra insulation to your heater. 

Here is how you can insulate the water heater:

  • Shop the water heater insulating blankets. 
  • Cut off the electricity from the water heater.
  • Cut the water heating insulating blanket for the height of the water heater. 
  • Now wrap the blanket around the water heater. 
  • Tape it temporarily. 
  • Mark the areas of control panels and valves. Cut those areas to have access to operate the heater. 
  • After cutting those areas, you can secure the blanket permanently around the water heater. 
  • Switch on the water heater now. Ensure that the thermostat’s temperature is 130°F because high temperatures after the insulation process will burn the material.

4. Replace the old water heater tank

As I said earlier, the average life period of a water heater is 10 to 15 years. 

If you tried and tested all the steps above and couldn’t fix the issue, your water heater has extended its average life period.

Replace it as soon as possible before your water heater puts you in the situation of taking a cold shower in winter.

How long should the water heater run?

A healthy water heater should run for 3-5 hours per day. 

You might know that a water heater will store the water in the tank and run water when you open the faucet.

A good water heater will take about 40-60 minutes to heat one tank of water.

It may vary depending on the insulation system and the length of the pipes.

Insulating the water heater is always advisable to maximize its efficiency. 

In case you have an electric water heater, it will take an hour to heat the complete tank.

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Why do I have to keep resetting my hot water tank?

If the red light in your water heating keeps fluctuating and you are constantly resetting it, something is wrong with your water heater. 

If your water heater is constantly tripping, here are the common causes for which you must take action.

1. Thermostat fault

If you have an electric water heater, it comes with 2 thermostats to regulate the temperature of the water.

When these thermostats become faulty, they will stay on all the time. 

Over time, a water heater will overheat and will start to malfunction. 

To fix this issue, consult a professional instead of doing this by yourself, which is risky.

2. Wiring issues

The wiring system in the heater keeps all the functions in check. 

If there is a fault in the wiring, the flow of electricity will fluctuate.

This may also be the reason for the constant tripping issue. 

Consult a professional to fix this issue.

3. Malfunctioning breaker

The breaker system which controls the water heater will start to deteriorate over time. 

The deteriorated breaker will cause the constant tripping of the electric water heater. 

It would be best if you repaired the breaker, or you could replace it based on the condition of the breaker.

How to maintain the water heater? 

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As a water heater is an important element of your home, maintaining it well is better than facing trouble later. 

Here are a few tips I thought of sharing with you to keep the health of your water heater in check. 

  • It would be best to do annual service maintenance for your water heater. It will avoid frequent issues.
  • Avoid keeping the geyser switched on for a long period. It will affect the efficiency of the water heater in the long run. Professionals advise you to switch it on before taking a shower.
  • It is best to set the water heater to a lower temperature. Doing this will reduce the workload of the geyser, hence increasing the life of the water heater.
  • Before winter arrives, check whether the anode rod is in good condition. If not, replace it to avoid the hurdles. Try to inspect the quality of the anode rod at least once in three years.
  • Use a high-quality electric socket and the wire because poor-quality sockets will burn when power fluctuation occurs. Make sure to use the MCB switch instead of the regular one, as it will withstand power fluctuation well compared to the regular switch. 
  • Finally, check the inlet and outlet pipes. It is wise to use metal pipes instead of plastics because they are better at withstanding heat than plastic pipes. 

Final thoughts

While inspecting the water heater to fix its issue of constant filling, check the drain valve, temperature valve, and connections. Follow the steps discussed in the article to fix the issues.

Working with the water heater is quite risky, and you must ensure the safety measures before starting the operation.

Some issues, like wiring connection issues of the water heater, need professional assistance; it is not advisable to do it yourself unless you are an expert in fixing these issues. 

Taking proper care and maintenance like annual checking, lowering the temperature of the water heater, and replacing the anode rods will save you from unexpected issues and trouble.

Reference: Wikipedia, Hot Water Tank Science Direct, Energy.gov.

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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