oil in water monitoring

March 14, 2024

Monitoring System to find oil in water

Do you need an economical way to continuously monitor how much oil is in your water to ensure acceptable discharge levels?

Our Oil Content Analyzer with electro-optical sensing can detect even trace amounts of oil in water flowing through a pipe – and send an alarm if the amount exceeds a certain level.

Applications include:

  • Aircraft and truck washdown facilities
  • Storm water runoff
  • Ground water reclamation
  • Oil Water Separator Effluent monitoring
  • Power plant effluent
  • Industrial process water discharge
  • Fuel transfer station rain water runoff
  • Bilge water discharge monitoring

The design is very straight forward. The monitor is attached directly to the pipe carrying the oil water mixture. Every 8 seconds, a small sample is taken through the pipe wall. A light source shines through the sample and the system measures how much light has been absorbed and translates that into oil concentration. After the measurement, the sample is put back into the water stream.

This oil content value can be adjusted to any level between 2 and 500 ppm (or higher, if needed). When the measured oil concentration is higher than the pre-set value, visual and audio alarms will activate. The alarm relay output can also be used to control valves, pumps and/or an external alarm circuit. Many other options can be added including 4-20ma outputs.


  • Self-Cleaning: Optical surface is cleaned each time it samples and expels water. Reduces maintenance and eliminates errors from fouled surfaces.
  • Completely Automatic Operation: Requires no attention from operators
  • Easily Installed: Just install through piping, no troublesome tubing
  • Reliable Sampling: Provides real-time results every 8 seconds without distortion
  • Rugged Design: Marine grade 316 stainless steel, bronze and aluminum.
  • Lightweight and Compact: Weighs less than 18 lbs (8 kg)


  • S. Coast Guard 162.050/3013/1
  • ABS OONN10170, 95-NN7502-X
  • IMO Resolution MEPC.60 (33).


Classifications NEMA 12, Optional Explosion-proof, High Temperature
Operating Fluid Temperature Up to 158°F (70°C)
Power 115VAC, 50/60 Hz 220VAC, 50/60Hz
Alarm Output SPST, 5 amp, 220VAC power failure relay
Alarm Local Visual Lamp and Audio Buzzer
Other Outputs 0 to 2 Volts DC for optional remote PPM digital readout and 4-20 mA
Pressure 0-50 psi
Measuring Range 2-500 ppm (or higher, if needed)
Measuring Accuracy & Repeatability +/-2 ppm at 15 ppm; +/-10 ppm at 100 ppm
Measuring Frequency 7 times per minute
Humidity Less than 90% non-condensing
Vibration Greater than IMO requirements, Roll, Pitch & Yaw: No restrictions
Size and Weight Sensor Unit is 15.75×7.1×5.9 in (40x15x18 cm) at 14 lbs (6.4 kg), and Control Unit is 13×10.6×8.7 in (33x27x22 cm) at 21 lbs (9.6 kg)
Options High Temperature (240F) version

NEMA4 Explosion Proof


4-20mA outputs

The Oil in Water content monitors and alarms are currently being used by over 350 different companies, in more than 40 different countries.

Call us today at 800-453-8639 for more information!


North Carolina


At WashBaySolutions.com, we have been specializing in high tech, custom-engineered solutions to complex washing and wastewater issues since 1991.
+ 1 800-453-8639




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