Why is there Oily Film Floating on My Water?

What Water Treatment Gets Rid of the Oily Film on My Water?

Have you noticed a strange oily film forming on the surface of your water? If so, you’re probably concerned about what’s in your water and how this may be affecting you and your family’s health. There are two main causes of oily film on your water: hydrogen sulfide, and iron bacteria.

Here’s a breakdown of how to tell the difference, what each issue means for your health, and what your water treatment solution should be.

How Can I Tell What’s Causing the Oily Film?

There are many different contaminants we have to watch out for that can get into our water. Many of those contaminants are toxic, and can cause serious short- and long-term health consequences when they enter our water supplies. Others may just give our water a cloudy, murky, or oily appearance or an unpleasant taste or smell, but not really be harmful to our health.

So, when you see that oily film, how dangerous is it? Is it really oil? How can you tell?

There are two main sources of oily film on water: hydrogen sulfide and iron bacteria. Here’s your trick for being able to tell the difference: stir the water with a stick. If you see the oil not breaking up when you stir the water, it’s most likely hydrogen sulfide. If the oily film breaks up when you stir it, it’s probably due caused by an iron oxide mineral.

What if It’s Hydrogen Sulfide?

Hydrogen sulfide is a gas that occurs naturally in some groundwater, especially well water. It forms when underground deposits of organic matter like plant material decompose. It’s also present in sewage treatment plants, as well as petroleum refineries and pipelines carrying crude oil and natural gas, as these are also sources of naturally-occurring hydrogen sulfide.

Hydrogen sulfide is typically only present in your drinking water in very small concentrations, so it doesn’t pose an immediate health threat. However, it does cause many other unpleasant effects, including:

  • Rotten egg smells, most present when hot water is first turned on.
  • Bad taste in food and beverages the water is used in.
  • Corrosion of metals like steel, iron, copper, and brass, which may affect plumbing.
  • Black or yellow stains on water fixtures.
  • Tarnished silverware and cookware.

These are all indications that your water contains hydrogen sulfide.

There are different root causes that could create this issue. If you have well water, it could be from rotting underground plant material, or because your well is drilled into shale or sandstone, or from nearby coal and oil fields. Alternatively, it could be the result of sulfur bacteria in your pipes. If the rotten egg odor only appears when the water is hot, it may also be due to your water heater’s magnesium rod.

What if It’s Iron Bacteria?

This is another common cause of oily film on water. Many people assume that an oily film indicates that there must be oil or some other petroleum product in their water, but that’s often not the case. If you did the stir test and the oily film easily broke apart, it likely means your water has iron-containing minerals and an excess of organic matter.

When iron-containing minerals like limonite or hematite come into contact with iron bacteria, they dissolve, and then when they come into contact with air they oxidize. That creates an oily-looking film, and can also lead to slimy rust-colored iron bacteria deposits. This is an especially common issue for homeowners who use well water. Excess iron bacteria can come from a well being drilled to close to an untreated pond or lake, or from using a worn-out well pump.

Even though this is unpleasant, this doesn’t typically cause any serious health issues. However, you’ll still probably want to look for a solution so you can enjoy clean, clear water.

What Should I Do About It?

If your water symptoms align more closely with hydrogen sulfide, your best bet for a water treatment solution is a whole house water filter. This system will remove hydrogen sulfide and other contaminants from your drinking water, eliminating the problem.

Still, since there are multiple different ways this substance can enter your water, we recommend you get your water tested and your water system inspected before you invest in new equipment. This way, our licensed plumbers will be able to assess the situation and give you the best recommendation.

If you’re dealing with iron bacteria, you’ll want to disinfect the water with chlorine. We recommend reading through our guide to well water, which includes a section on shock chlorination for eliminating iron bacteria.

However, the best way to get rid of iron bacteria, and oily film on your water, is with a chlorine injection system like Angel Water’s PurAclear Chlorine Injection and Whole House Filtration System. This well water filtration system keeps your water supply properly chlorinated at all times, so won’t have to worry about this issue periodically coming back, the way iron bacteria often does. It also filters all your water before it reaches your faucet, so you’ll always have access to clean water at every fixture in your home.

Need More Assistance?

If you’re still wondering what else might be in your water (and we don’t blame you), then we again recommend you get your water tested for contaminants. Angel Water’s water experts will even drop by to collect the water for testing—give us a call today!

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