Fuel oil heating systems get their fuel from heating oil tanks that are stored onsite. Instead of relying on utility pipelines, homeowners have their own supply that is replenished through oil deliveries. Although this setup is very useful and ensures continuous heating, it is important for homeowners to be aware of how to best care for the system. One of these is the unwanted introduction of water inside the oil tank or oil tank condensation.
The Basics of Oil Tank Condensation
- The Basics of Oil Tank Condensation
- How Water Infiltrates Home Oil Tanks
- What Happens If Water Moves into the Heating Oil Tank?
- How To Prevent Heating Oil Tank Condensation
- Exterior Oil Tank Inspection
- Tank Interior Water Testing
- Avoid Extreme Heat
- Maintain a Full Oil Tank
- Call the Pros
- How Professionals Draw Water from Oil Tanks
- Potential Dangers of Keeping Water in an Oil Tank
- Conclusion
- Contact The Better Home Heat Council For Your Home Heating Requirements
Let’s start by discussing the reasons behind oil tank condensation and the ways in which it may be avoided.
How Water Infiltrates Home Oil Tanks
Water is universal and persistent. It can change its form depending on the environment and make its way through most barriers. If you know how it does this, then you are one step closer to stopping it from reaching the oil tank.
Rainwater
The location of the heating oil tank is crucial. Those installed outdoors are vulnerable to rain exposure. During the wet season, water can get into various entry points even if there are caps and lids. You need to check these from time to time to make sure that they are sealed and screwed tightly. Fuel oil tanks may also get splashed with water from gutter run-off. Old tanks with weak walls may allow water to seep in through their surface cracks.
Condensation
Consider the possibility of condensation. Vents can let humid air inside the tank. The water vapor may turn from gas to liquid if the interior temperature gets cold enough. This is true whether the oil tank is indoors, outdoors, or underground. Droplets will form across the interior wall and move down the tank. A bit of moisture is tolerable but a large quantity is a big headache.
Groundwater
Some tanks are buried underground to save space and reduce eye sores. This provides them with a degree of insulation, but it doesn’t prevent corrosion. As they get older, the tank walls will weaken and develop holes. Water can move from the soil to the tank interior. The reverse can be just as troubling, with oil from the tank contaminating the soil. Professional cleanup will be necessary if this happens.
What Happens If Water Moves into the Heating Oil Tank?
Idealistically, oil tanks should be filled with nothing but oil. Anything else could interfere with the system’s performance and efficiency. If water manages to make its way inside, which occurs in all oil tanks, owners may not immediately feel a change. Damage will occur gradually and manifest with symptoms. It is important to catch this at the earliest stages to prevent problems in the future. Detection can be a challenge because visual inspection has limited use, particularly for underground installations.
Proactive water detection is the key to a longer-lasting oil tank. Don’t wait for symptoms to show. Perform regular oil tank inspections using proven techniques to find out if you have water in the tank. The homeowner can do some of these on their own, although they can seek the help of heating oil specialists for more accurate results. They may dip water-sensitive paste to the bottom of the container and check of discoloration. The pros can then move in to remove moisture and ensure proper disposal.
How To Prevent Heating Oil Tank Condensation
Now that we know how water enters oil tanks, we can take things a step further and prevent this phenomenon through different strategies depending on the situation.
Exterior Oil Tank Inspection
Homeowners can start with a simple exterior inspection of the tank surfaces and openings. Walk around the container to check whether there are visible holes, cracks, rust, or paint chips. Try to reach the caps and lids to see whether these are closed tight or not.
Tank Interior Water Testing
Water may already be present in the tank without you knowing about it. Since water is denser than oil, moisture tends to make its way down the container so you won’t see it if you just check the surface. Just should test what’s on the bottom. This is often done through a special paste that changes color upon contact with water. Ask heating oil experts about good options on the market. If you have an underground tank, then you should also test the soil for possible oil contamination.
Avoid Extreme Heat
New oil tanks should be installed with attention to heat exposure. Shield them from extreme heat by placing them in a shaded area. You may also paint the exterior with a reflective coat with a light hue. By managing tank temperature, it will be easier to minimize condensation.
Maintain a Full Oil Tank
As oil gets used up, empty space in the tank gets bigger. Moist air fills this up, increasing the likelihood of condensation. Read your oil tank gauge and try to prevent the oil level from getting too low. Call for oil delivery to reduce the amount of air in the tank. Monitor this regularly so that you can act quickly when necessary.
Call the Pros
Homeowners can perform basic inspections and maintenance on a regular basis. They have the advantage of having the tank on their property, so they can always monitor its condition. However, they do not have the skills and experience necessary to perform advanced tasks. These require professional assistance for safety and efficiency.
How Professionals Draw Water from Oil Tanks
If you have confirmed the presence the moisture in the tank, then you must act on it as soon as possible. Call the professionals to remove water from the storage unit. They can try different methods based on the circumstances.
- Drain: Since this issue is common, metal tanks are designed with sludge valves to quickly drain the water from the bottom. Catch the liquid as it flows out because oil may come out with the water and make a mess. Dispose of this properly.
- Pump: Unfortunately, sludge valves are not present in plastic tanks. Alternative means must be employed for water removal. For example, using a manual hand pump can be sufficient in drawing out small amounts of liquid. However, larger volumes may require professional equipment.
- Absorb: Another way to get the water is to dip an absorbent material in the oil tank. By catching moisture early, you can prevent water from pooling at the bottom of the container. These materials can only hold a limited amount of moisture, so be sure to replace them from time to time. It may also be possible to employ an alcohol-based dispersant.
Potential Dangers of Keeping Water in an Oil Tank
- Oil Tank Rust: If you neglect the tank despite the presence of water, then you will have to contend with container damage later. Rust is one of the most common problems for metal tanks. The tank walls will suffer from corrosion from the inside and spread throughout the system. Heating performance may decline as a result.
- Freezing: It’s fine to leave oil outside in winter since it has a low freezing point. It will remain in a liquid state and provide energy for the heating system. However, the same is not true for water that gets into the tank. This may freeze and prevent oil from moving through the supply lines.
- Bacteria: Bacteria loves moisture, so it’s no surprise that it will thrive in oil tanks with high water content. These can form sludge that blocks openings and releases corrosive substances. If this spreads across the system, then it will be a big problem.
Conclusion
Heating oil tanks should hold fuel and nothing else. If water gets inside, then it should be removed as early as possible. Homeowners should be vigilant in checking for signs of moisture. If a large amount of water is trapped at the bottom, then professionals should step to help.
Contact The Better Home Heat Council For Your Home Heating Requirements

The Better Home Heat Council (BHHC) is a local association that aims to help homeowners with everything that has to do with fuel oil heat. We provide you with knowledge, especially on things regarding the economic and efficient use of heating oil. Also, we assist people in identifying and solving issues about energy efficiency in their homes or office. We accomplish this by pushing them towards an effective and affordable path to ensure that their living areas become more efficient and cost-effective.
The BHHC also supports heating oil delivery service companies that offer services, products, and solutions to homeowners in the Lehigh Valley. If you are searching for a superior full-service home heating oil delivery company near you, click here. Rest assured that most of the fuel oil delivery service companies in our system also provide HVAC services and free energy consultations.
For questions and concerns concerning your HVAC system or oil delivery, click here to contact the Better Home Heat Council today.