How Does Water Get Into An Oil Tank?

water in oil tankA heating oil tank can last up to 20 years if properly maintained. One of the quickest ways to shorten a tank’s lifespan is to allow water to enter and remain inside. Checking for and removing moisture in your tank can lengthen your tank’s years and prevent heat loss when you need it the most.

Both above-ground and below-ground tanks are susceptible to many of the same threats. Rainwater or runoff can enter your tank through any opening – a crack or puncture, a poorly fitting or loose filler cap or inspection lid, an uncapped fill pipe, a corroded seal, or an open or damaged vent. Tanks located near your house – especially under your roof’s drip line – are susceptible to water intrusion through these openings, even when you think your tank is adequately shielded.

Condensation is another common way for water to enter an oil tank. Above-ground tanks that are in direct sunlight are especially vulnerable to condensation.

Is Water In Your Oil Tank Bad?

Water can wreak havoc on your oil tank, and it can corrode your tank, cause leaks, and contaminate your fuel supply. This can damage your entire heating system – wasting fuel, costing you money, and leaving you out in the cold.

What Happens If You Get Water In Your Oil Tank?

The most dramatically noticeable result of water in your oil tank is when the water freezes and you cannot heat your home. Home heating oil has a low freezing point, but water freezes at 32 degrees Fahrenheit. Frozen water in your tank can ultimately interfere with oil flow, leading to a system shutdown and loss of heating.

Over time, water can corrode the bottom of your oil tank and damage fuel lines and nozzles. When water remains in your tank, it causes corrosion to occur from the inside out, resulting in leaks and a decline in your system’s efficiency.

A corroding heating oil tank could also leak eventually. Homeowners might notice leaks in an above-ground tank faster, whereas a small leak in an underground tank might be around for a while before it’s detected. Either way, a leaking oil tank can cause environmental problems.

Water is denser than heating oil, and once inside your tank, it sinks to the bottom. At this point, microorganisms can grow and multiply in the water. As they die off, they combine with other sediments, like dirt and rust, and create sludge in your tank, causing additional corrosion and contaminating your fuel supply.

How Can I Tell If There Is Water In My Oil Tank?

Unless the tank or one of its components is leaking or rusting, a visual inspection of the tank is probably inadequate. You can perform a quick test yourself or have your heating oil service provider do a more thorough examination.

Most hardware and plumbing supply stores carry testing kits to determine the water in your tank. The test involves placing a special water detection paste on a stick and dipping it to the bottom of your tank for 30 seconds. If the paste changes color, water is present.

The easiest and most comprehensive way to find out is to ask your fuel service provider to test for water in your oil tank. They are best equipped for removing the water and sludge following EPA regulations.

How Can You Get Water Out of Your Heating Oil Tank?

You may be able to remove a small amount of water yourself. If there is only an inch or two of water, you can try to drain, pump, or absorb it. Anything more than that should be addressed by a professional.

Many metal oil tanks have a sludge valve on the bottom, and opening it will drain most, although probably not all, of the water. If your tank does not have a sludge valve, you can siphon out the water with a small pump. Some oil will also drain in both cases, so the oil must be collected and disposed of per local and federal regulations. Do not, under any circumstances, empty it onto the ground or pour it down a drain. This is another reason why it’s best to let a professional handle it.

There are also products designed to absorb small amounts of water in your oil tank. Hardware and plumbing supply stores sell chemically-treated water-absorbing “socks” to be inserted into your tank for a specified length of time and then removed. They soak up water, leaving the oil behind, and these only remove about one to two cups of water so that you may need more than one sock.

Additionally, an alcohol-based dispersant may be added to your tank to absorb water, and some help to break up sludge. Many oil providers offer regular dispersant use as a lost-cost add-on service, which is the quickest and easiest way to deal with the issue. During colder months, your provider can add a low pour temperature stabilizer to help prevent freezing.

Whichever method you choose, a licensed technician should change the oil filter after removing water from your tank, the boiler feed pipe flushed, and any underlying cause for water in the tank addressed. Unless you are highly experienced, it is advised to leave these tasks to a professional.

Do You Need to Have Your Oil Tank Cleaned?

Regularly scheduled maintenance is essential to prevent water damage to your oil tank and the rest of your heating system, so you should plan for your tank to be cleaned every three to five years. This is a job best done by your oil supplier, as it involves pumping out the tank’s contents, which a technician must do in compliance with environmental regulations. Between cleanings, dispersant, and temperature stabilizer treatments, these significantly reduce your odds of having issues with water in your tank.

Call Tragar Express and Keep Your Oil Tank Full

When it’s time for a heating system maintenance or upgrade, call the experts at Tragar Home Services. We offer extensive services for oil heat and gas heat systems. Our parent company, Tragar, has been keeping Nassau County and Suffolk County residents comfortable for more than 60 years. For information about heating system upgrades or scheduling a COD oil delivery, call Tragar Express today at (516) 221-2559. You can also email us at