We are often asked if minor leaks are really much of a concern. Repairing them takes valuable time that most maintenance shops feel should be devoted to issues that could halt production. Everyone knows that a ruptured hose needs to be addressed right away. But the mistaken belief that a minor leak doesn’t cause a problem is certainly not uncommon. It is even a little surprising how many people seem to believe that hydraulic machines are “supposed to leak a little”. We have heard everything from “The oil that bypasses the cylinder seals helps to keep the rods lubricated” to “The leaks in our system help keep our oil fresh since we have to replace so much of it all the time”. These same people however would be quite dissatisfied if their automobile’s power steering pump, automatic transmission or brake lines “leaked a little bit”.

So how much does a minor leak cost? To answer that question, we have to first explore all of the costs involved. Most people think that the only cost is the amount of oil that has to be unnecessarily replaced. But this is not the only cost associated with hydraulic leaks. The actual costs include:

  • Replacement Oil
  • Safety
  • Environmental Concerns
  • Cleanup Costs
  • Disposal
  • Contamination
  • Loss of Machine Efficiency

Replacement Oil

This is the most obvious cost. A single drop of hydoilraulic oil doesn’t cost very much even at today’s prices. But if your system loses a drop of oil every second, it adds up. A drop every second will equal over one gallon per day, more than 35 gallons per month and about 425 gallons per year. Depending on your geographic area, the type of oil you use in your machine and the volume you purchase you pay on average about $10 per gallon – considerably more for specialty oil. This means that a leak that loses one drop per second (most systems lose many times that) is costing you about $4250.00 each year in replacement oil alone.


The cost of replacement oil is bad enough but oil leaks pose a safety hazard in almost every facility we have visited. The cost of safety hazards is hard to calculate. But even one incident can cost a few hundred dollars or a few million.

Environmental Concerns

Not everyone agrees with the Environmental Protection Agency’s standards and policies, but one thing we can all agree on is that it is unlikely that EPA requirements will become more lenient in the near future. If any changes are made in EPA standards, they are likely to include stricter controls and heavier fines and penalties. Here in Georgia where GPM is located, an uncontained spill of more than one gallon can require EPA notification. For large leaks, fines in the millions of dollars are not unheard of.

Cleanup Costs

Often the costs of routine cleanup are ignored, but that doesn’t make them go away. Time devoted to cleaning up from a leak is time that could be spent on more productive endeavors and could result in overtime costs that would otherwise not have to be incurred. And we cannot ignore the cost of cleanup equipment, absorbent pads and detergents. Most people are not aware that pads and absorbent material cost more than the oil they pick up. Unless you make it a practice to wring out those absorbent pads and reuse them (not a very common practice in our experience), that brings the cost of our one-drop-per-second leak to $8500 for the year!


Those of us who can remember a time when waste oil companies paid for the privilege of coming to empty our waste hydraulic oil tanks can probably also remember getting change back from a five dollar bill after having someone else fill up our gas tanks, check our oil, check our tire pressure and clean our windshield. These days, depending upon your location, an environmentally acceptable means of disposing waste oil can cost $3 per gallon (or more if the oil has water in it). There’s another $1275 annual cost to our minor leak.


It’s easy to forget that if oil has a way out of the machine, contaminants have a way in. Airborne contaminants, particles and water all can wreak havoc with a hydraulic machine. Over 96% of all hydraulic failures can be directly traced to contaminants in the oil. Not all of those contaminants come from an oil leak of course, but any that we can stop will pay big dividends in parts that do not have to be changed unnecessarily, reduced down time and greater intervals between flushing or changing the oil.

Loss of Machine Efficiency

A machine that leaks is working harder than it has to. This means that, while the machine appears to be functioning as it should, our energy costs have increased. Suppose our one-drop-per-second leak causes the power bill to increase by five cents per day. That’s another $18.25 in annual cost. Not a huge amount, but it could probably buy us dinner somewhere. And it adds up if it occurs in several machines.

So assuming that no one gets hurt from slipping on oil and the EPA doesn’t have to visit, each one-drop-per-second leak can cost upwards of $10,000 every year. And hydraulic leaks, unlike paper cuts, do not heal. They gradually get worse. At some point, what starts as a “minor” leak can become a system outage. No leak is so minor that it should be ignored. Are there any minor leaks in your systems? One of the criteria of our customized reliability assessments is to identify leaks in the system.