Water in Oil Storage Tanks
An owner's guide to preventing, or measuring & removing oil tank water contamination

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Water accumulation in an oil tank from flooding or from leaks into the oil storage tank:

Why is water in an oil tank a problem? How water gets into an oil storage tank - assessing the level of water in an oil tank: water finder paste, instruments, visual inspection .

This article series explains the problems caused by water accumulation in oil tanks, how water gets into the oil tank, how to measure water in the oil tank, how to remove water from oil storage tanks regardless of whether the oil tank is indoors, outdoors above ground, or buried, and how to prevent water from getting into an oil storage tank.

We explain how to test for or visually check for water in a buried or above-ground oil storage tank, and how to get water out of an oil tank. Extensive free un-biased oil storage tank inspection and testing advice for property buyers and owners is provided at this website.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Testing for and Removing Water Contamination from Oil Storage Tanks

What problems are caused by the presence of water in heating oil or heating oil tanks?

Photograph of an oil tank filler flush with the ground.According to R.W. Beckett, a major manufacturer of heating oil burners and related equipment, water in the heating oil tank or piping system causes the following "nuisance service problems" problems [edited, paraphrased, amplified - Ed.]:

Testing an oil tank for for water contamination in an oil tank (above ground oil tanks whether inside or outdoors, or buried oil tanks) is simple and can be done by any service person or even a homeowner.

Oil Tank testing methods for oil leaks vary in risk to the tank, cost, invasiveness, length of time to complete, and more.

Since water in a heating oil tank can lead to loss of heat and related building damage we want to know if in-tank water is a problem at a given property. There are several steps and test methods for finding water in an oil tank and for determining how much of a problem it is.

How Does Water Get Inside a Buried Heating Oil Storage Tank

Details about how water leaks into or condenses in buried oil tanks are at BURIED OIL TANK WATER ENTRY. Excerpts are below.

How Does Water Enter an Above-Ground Oil Storage Tank

Details about how water leaks into or condenses in above-ground oil tanks are at  ABOVE GROUND OIL TANK WATER ENTRY. Excerpts are below.

Sources of water entry into above ground oil storage tanks are similar to the underground oil tank water leak sources listed just above.[Paraphrased, edited, and expanded from R.W. Beckett]:

Steps to Reduce the Chances of Water Entering an Outdoor Above-Ground Oil Storage Tank

Details about how we keep water out of oil storage tanks are found at OIL TANK WATER PREVENTION. Excerpts are below.

[Paraphrased, edited, and expanded from R.W. Beckett and other sources]:

How to Measure the Level of Water Contamination in an Oil Tank

Oil storage tanks would ideally be tested for water accumulation at every oil delivery, but as that simply is not going to happen, you should ask your oil company to assess the amount of water in the oil tank at least once a year by using one of the methods discussed at OIL TANK WATER DETECTION where we provide details about measuring the level of water contamination in heating oil tanks. Excerpts are below.

A simple method that can be used on oil storage tanks whose fill pipe is located directly above the tank is to insert a dipstick into the oil tank after coating the dipstick end with a water-finding paste. (photo at left).

A similar test for oil tanks whose piping does not permit use of a dipstick makes use of a string and weight and water finding paste.

Where to Buy Oil Tank Water Finding Paste or Water Indicating Pastes

Other Methods for Detecting Water Contamination in a Heating Oil Tank

Ask your oil company service technician to check the oil filter for evidence of water or rust, or if you've had heat outages ask if water in the oil could be a contributor or cause.

See OIL TANK WATER DETECTION for details about methods of testing for water in oil storage tanks.

Foam Formation in Wet Heating Oil

Reader Question: foam formed when new oil was put into tank that caused it to indicate full and stop pumping

14 Feb 2015 Anonymous said:

I asked the oil man to fill my tank that read 1/8 tank. When he came he pumped 110 gal and it indicated full to delivery man. The guage read 1/2. They told me that foam formed when new oil was put into tank that caused it to indicate full and stop pumping. I've never heard of such a thing! Any comment?



What you describe is not something I've come across but it has been described as an effect that can occur if there is water contamination in the oil storage tank; during delivery the incoming oil, delivered fast and under pressure, can stir up water and form foam - this can also clog up the heating oil piping, filter, burner, and lead to loss of heat.

I'd ask the oil company to check oil tank water level, remove excess water, and go from there.

I'd also check - if you can - about just what was being delivered to you - if your oil tank didn't have much water in it before then water could have come in a bad delivery. I've seen this happen if the oil truck is filled from a depot tank that is low on oil, has water in that tank bottom (which is normal) and is itself stirred by a depot delivery while the oil truck is filling.

Experts have written about this, describing the formation of a water-oil emulsion and problems that it causes in heating oil production and usage; see in parcitular Maslennikov (1969)

This Q&A was originally published at OIL TANK GAUGES

How to Remove Unwanted Water from an Oil Tank

Details on how we get rid of water contamination in an oil tank are now at OIL TANK WATER REMOVAL

Articles at this website describe what to ask about home heating oil storage tanks, what oil tank leak tests to order if you are buying or selling a home with an oil tank, how to prevent loss of heat due to oil tank sludge or water contamination, how to interpret oil tank testing results, what to do if there is a buried fuel or petroleum storage tank at a property, what to do if there is or was a leaky oil storage tank or petroleum storage tank, and how to reduce the chances of an oil leak or oil spill in the future.

We include detailed information about underground (buried) oil storage tanks (USTs), aboveground oil storage tanks (ASTs), above ground fuel storage tanks, reporting and cleaning up oil tank leaks, and choosing among oil tank leak testing methods.


Continue reading at ABOVE GROUND OIL TANK WATER ENTRY or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see these

Aboveground Oil Storage Tank Water Contamination Articles

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OIL TANK WATER CONTAMINATION at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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