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Common Ground News

What happens if water gets in hydraulic fluid?

Author

Christopher Snyder

Updated on February 23, 2026

What happens if water gets in hydraulic fluid?

Water in hydraulic oil has a number of negative effects: Depletes some additives and reacts with others to form corrosive by-products which attack some metals. Reduces lubricating film-strength, which leaves critical surfaces vulnerable to wear and corrosion. Reduces filterability and clogs filters.

Accordingly, how do you get water out of hydraulic fluid?

A second option to remove water is to use water-absorbing filter elements. Most standard return line filter assemblies are available with media to remove free water. By changing the standard element with a water-removing element, you can slowly trap the free water as the machine is running.

Likewise, will water settle out of hydraulic fluid? Zoller said that because water generally has a higher specific gravity than hydraulic fluid (exceptions do exist e.g. HFD-R), it tends to settle at the bottom of the reservoir when given sufficient resident time in a still environment.

Also know, how do I know if my hydraulic fluid has water in it?

There are two simple ways to determine on-site if engine oil or hydraulic fluid contains water: 1) Look at the system and if the fluid is milky in the area of the breather or fill cap/dipstick, more than likely there is moisture above the normal saturation point.

Is hydraulic fluid spill dangerous?

In people, the effects of breathing air with high levels of hydraulic fluids are not known. Drinking large amounts of some types of hydraulic fluids can cause pneumonia, intestinal bleeding, or death in humans. Weakness of the hands was seen in a worker who touched a lot of hydraulic fluids.

How do I remove water from my transmission?

How to Get Water Out of Transmission Fluid
  1. Put the car in park and engage the emergency brake.
  2. Jack up the vehicle so that you can reach the transmission pan.
  3. Replace the drain plug and refill the reservoir with transmission fluid.
  4. Locate the cooler-out line, which takes oil from the transmission to the cooler.

Can I mix ATF and hydraulic oil?

Don't mix them. You may use one or the other but not both mixed.

What causes water in hydraulic system?

Because of its affinity for other liquids, water is present in some concentration in most hydraulic systems. The hygroscopic nature of liquids causes them to pick up a certain amount of water simply from contact with humid air.

What color should hydraulic fluid be?

Most hydraulic fluids are based on natural or synthetic oils, which are typically some shade of brown, from yellowish golden to nearly black. Generally they start out very light-colored, and turn darker the more they are used, from wear particles and from thermal decomposition.

What are the effects of breathing in hydraulic fluid?

Up to a measurable degree, the inhalation won't cause any health issues. But after that limit, it will irritate mucous membranes in the throat and respiratory organs. It may cause asthma-like shortness of breath, headache, fatigue, dizziness and nausea. This will be a result of overheating of hydraulic fluids.

Why is hydraulic fluid toxic?

Occasionally, some hydraulic fluids can cause skin drying and irritation. Swallowing one of the oily hydraulic fluids, like the synthetic hydrocarbons, is potentially dangerous. These products have a tendency to get into the airway more easily than water-based substances.

Will hydraulic oil kill plants?

Unfortunately, once hydraulic fluid has come into contact with grass blades, they will suffer some damage. Still, leaving hydraulic fluid in the soil can cause permanent contamination that can affect the growth of all future grass in the area, possibly killing it.

Is hydraulic fluid good for the skin?

Because hydraulic fluids are made up of chemicals and additives, they can be extremely irritating to the skin. Protect exposed skin from the liquid and immediately use soap and water to wash any areas that came into contact with the fluid.

Can hydraulic fluid be absorbed through the skin?

Exposure to hydraulic fluid can occur through touch, injection, ingestion, and inhalation. Touching some hydraulic fluids may cause weakness in the hands or burns to the skin depending on the chemical make-up of the fluid.

Is hydraulic fluid bad for environment?

Mineral oil hydraulic fluids are produced from crude oil. Hydraulic fluids can enter the environment from spills and leaks in machines that use them and from leaky storage tanks. If spilled on soil, some of the ingredients in the hydraulic fluids mixture may stay on the top, while others may sink into the groundwater.

What happens if you get hydraulic fluid under your skin?

Hydraulic fluid or fuel entering the bloodstream can quickly result in death since the human body has no defence against it. If that weren't serious enough, bacteria can be driven deeply into the wound causing dangerous infections.

Is hydraulic fluid flammable?

Hydraulic fluids for the most part are considered to be much less flammable than middle distillate fuels. Petroleum-based hydraulic fluids have high flash points, while water-based hydraulic fluids (because of their high water content) are definitely nonflammable.