Water Level Sensors

There are hundreds of transducer type sensors in the market today. There are a few things that set them apart. Most of these type of sensors use pressure on a thin wafer type sensor to measure the depth of water or even the pressure of the air. The other main sensor type is called a vibrating wire piezometer. This sensor uses a tiny wire and measures the vibration frequency of the wire when plucked by the sensor. The depth of the water changes the frequency of the wire.

Built-in Dataloggers

Some of the pressure sensors available have a built-in datalogger and these are often used in ground water monitoring due to their small form factor and ease of use and installation. We sell and support the Campbell Scientific CRS451/CRS456 water level and temperature dataloggers, and the Onset HOBO Water Level Loggers. These sensors have built-in dataloggers and are easy to deploy for measuring water levels in a variety of applications.

Datalogger and Sensor Integration

By combining a pressure transducer or vibrating wire sensor with one of the Campbell Scientific dataloggers you can create a rugged and flexible water level monitoring system. The  CR300 series, CR800 series, and CR1000 dataloggers can read many different types of outputs and offer reliable data collection and can be implemented as a control system or warning system in many types of applications.

There are many sensors available these are a few we recommend. Contact us if you need something else; we can generally match what you are seeking.

SENIX Ultrasonic Sensor – Water Level or Distance Measurement

For general distance ranging and benign liquid level applications, including irrigation, flood monitoring, object detection or selection, and general industrial automation. These are the flagship products for Senix with heavy-duty electronics epoxy potted into type 316 stainless steel housings, with permanently attached cables and ruggedized piezoelectric transducers. ToughSonic sensors are found on remote monitoring stations from the Australian outback to Alaskan oil fields. They are installed on heavy construction and farm equipment and in some of the harshest factory environments.

Senix ultrasonic sensor installed over a creek in Tennessee measuring flood stage

Maximum Range Model
50 ft (15.2 m)

Environmental
Temp: -40 to +70C operating
Humidity: 0-100% RH
IP68 ingress protection

Compliance
CE

Outputs & Interfaces
2 and 5 output models
Voltage, current, switch(es)
Serial data RS-232 or RS-485

Cable (custom lengths available)
6.5 ft (2 m) pigtail

The OTT-CBS is a compact bubbler that generally measures ground or surface water level, but can also measure any liquid level. This bubbler has an accuracy of ±0.02 ft. A Campbell Scientific datalogger controls the OTT-CBS pump and calculates the measurements. The bubbler typically communicates with the datalogger via the SDI-12 protocol, which is supported by many dataloggers.

OTT-CBS Benefits

• Ideal for areas where submersed sensors can be damaged due to corrosion, contamination, flood-related debris, lightning, or vandalism
• Compatible with most Campbell Scientific dataloggers
• Easy to maintain
• Robust pump design provides reliable operation
• Consistent accuracy ensured by drift-free measurements and offset compensation using relative measurement
• Purge function clears the measuring tube and the bubble chamber of contamination
• Does not use pressurized nitrogen tank—requiring less frequent attendance
• Existing tubes can be used

The potentiometric float and pulley water level sensor is a modernized version of a time-tested sensor technology. The sensing mechanism consists of a float and counter-weight which are attached to a flat tape or ladder chain. The tape or chain runs over a pulley wheel. The openings on the tape or chain mesh with the notches in the pulley wheel to give a positive drive.

As the water level rises or lowers, the float goes up and down, thus turning the pulley wheel. The pulley shaft is coupled to a precision 10-turn potentiometer. The potentiometer converts mechanical changes into electrical changes. Changes in the potentiometers resistance are detected by the measurement system. The measurement system converts the potentiometer output to digital form and converts the results to the appropriate units of water level (i.e feet) change.

The pulley wheel circumference is 12 inches so that each full turn of the potentiometer corresponds to a one foot change in water level. A 10 foot change in water level can be measured.

We can build any type of stilling well for your water level measuring project. We build stilling wells out of steel corrugated pipe and PVC products.

We can supply nearly any diameter, but we have some standard sizes that we recommend.

• 8″ Corrugated Steel
• 12″ Corrugated Steel
• 24″ Corrugated Steel
• 36″ Corrugated Steel
• 12″ PVC Pipe
• 24″ PVC Pipe

All of our still wells come with a 3/4″ or 1″ access coupler or nipple at the bottom of the well, this allows you to attach a PVC or steel pipe to the well for water access. All of our wells also come with a shelf or flange(s) at the top for attaching a cabinet or enclosure. If you would like we can also provide the cabinet or enclosure based upon your requirements.

Above is an example of a USGS type stream Gage system. Most often a simple corrugated pipe and cabinet are now installed for low cost and ease of use.