Ultrasonic level measurement uses sound to measure the level in a tank or vessel. It has been widely used in the water & wastewater industry for many years. A Water Online article, Level Measurement Showdown: Ultrasonic Vs. Radar compares and contrasts the two technologies.

I mention this because of the popularity of a post, 4 reasons why radar level is superior to ultrasonic level technology by Emerson’s Vladislav Snitko. He cited radar’s advantages, including stability in differing ambient conditions, stability in changing process conditions, ease of setup, and price.

The Water Online article author noted that ultrasonic has been the historical leader in flow and level measurement in this industry. What was once a wide price differential between the two technologies has been significantly diminished.

The average ultrasonic level measurement instrument costs $500 to $2,000. Radar level measurement instruments used to cost up to $4,000 but now have dropped down to $1,000 to1,200 on average, putting the two instruments at a nearly level playing field in terms of cost.

One consulting engineer in the article recommends:

…radar level measurement instruments to his clients that work in wastewater because oil, grease, and other coatings can sometimes interfere with the accuracy of ultrasonic measurement instruments.

Another challenge with ultrasonic measurement highlighted by a flow compliance and regulatory efficiency manager is the environmental conditions.

Dust, foam, and cobwebs can also present problems for ultrasonic level measuring instruments, and measurement accuracy can be affected by wind, temperature, and snow in outdoor tanks.  Radar doesn’t have these limitations…

Some view ultrasonic meters as more straightforward to use but useful for a narrower range of applications. The biggest advantage, at least in the water industry, is that ultrasonic has long been the incumbent, and these devices can operate effectively for 10-15 years, as described in the article.

New installations and retrofits may well consider non-contacting radar level measurement advantages in stability from changing process and environmental conditions.