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The Difference Between Wet and Dry Leak Detectors

Today's industrial world includes multiple complex procedures, ranging from government labs to classified defense activities. Some of them require their systems to be pressurized or depressurized to exact specifications to function efficiently - and when they do, leak detection systems become vital.

There are various leak detector setups and testing modes available, but to select the best one, you must first understand the difference between the two basic types: wet and dry.

How Do Leak Detectors Work? The Difference Between Wet and Dry Leak Detectors

Leak detectors quantify fluid or gas leakage in pressurized or evacuated systems, as their name indicates, or pinpoint the precise position of a leak in a component.

Leak detection principles are complex, but in their most basic form, leak detectors are a type of non-destructive testing (NDT) that detects the quantity of air escaping from a machine or industrial process. It detects the partial pressure of helium within a vacuum pump's suction tubing.


Leak detectors are utilized in several industries since many applications demand a pressurized or vacuum system. Among the most popular leak detection applications are:

● Medical device production

● Pharmaceutical production and laboratories

● Manufacturing procedures

● Aerospace

● R&D

● Particle accelerators

Dry VS Wet

While you need to consider additional factors, the application should be the defining factor when selecting a leak detection system. Wet systems use oil in their vacuum pump so oil vapors may be released during operation. Dry leak detectors do not utilize oil and so produce no emissions. If your application demands that no oil vapors be released, you should purchase a dry leak detector.

Here are a few other variations between the two.


A Wet leak detector must have maintenance done once a year unless it is used infrequently. A typical yearly maintenance schedule includes oil and filter replacements and cleaning. Oil color, oil smell, and excessive background levels are all indicators that maintenance is required. Maintenance counters on modern leak detectors automatically warn the operator when it's time for it.

Dry leak detection systems need less maintenance since no oil is required in the vacuum pump. Most dry leak detectors only require it every two years.


Wet and Dry leak detectors are both highly durable and dependable devices expected to survive up to 10 years in clean settings. Dry systems are less difficult to maintain since they do not require oil changes or disposal. Both wet and dry leak detectors include air conditioning filters to preserve the electronics, which must be serviced based on usage.


Wet and dry leak detectors are both developed with simplicity, matching their durability. They use the same software and perform virtually identically, with the sole distinction being the helium leak rate tightness of the dry vacuum pump types. Both systems can perform the sniff, internal vacuum, over-pressure vacuum, and external vacuum tests.


Since they are manufactured identically, there is minimal pricing difference between a wet and dry leak detector. Dry systems cost 3-5% more than wet systems, although the savings from reduced maintenance may offset additional costs.


The first factor to consider when selecting a dry or wet leak detector is satisfying predetermined standards. A-VAC is here to help you if you have doubts or need advice on choosing a leak detector. Contact us today!