Some water level sensing applications and controls require more than a sensor or indicator–they need a water level indicating alarm. At Waterline Controls™, we have the low water level sensor alarms and high water level sensor alarms that you need.

Typical Usage

One of the most popular systems we offer is a controller with a fill, high alarm, and low alarm. Cooling tower mechanical contactors especially like it because it provides the operator with the most key information about the water levels in the cooling towers — and it connects seamlessly to their existing BMS. The BMS connections allow the operator to know the fill cycles, if it goes into either high or low alarm mode, or if it happens to lose power. And it works in any environment that needs water level alarms — including sump tanks, well water tanks, fire protection tanks, water system surge tanks, and much more.

Examples of Waterline Control Solutions

Our WLC 5000 controller provides Fill with High Alarm. It uses a 3-contact point system with 8-wire dry contacts to BMS for measuring Fill “ON” time, Low Water alarm, High Water alarm, and fault conditions. It operates on any any 110VAC valve & 110VAC audible alarm (not supplied in this kit, but available). It comes with 50’ of sensor wire, the controller, and, of course, the sensor with mounting assembly. The WLC 5000 provides three key outputs: close a set of dry contacts for a BMS, operate a relay rated at 30 AMPS / 250VAC, and turn on an LED to indicate that the sensor has tripped.

The WLC 6000 controller is similar to the WLC 5000, providing Fill with High / Low Alarms and Low-Low Heater Cut Off. It monitors for a high water level condition, a low water level condition, and a Low-Low Level condition for Heater Cut-Off. This a popular product we provide to OEMs that are putting submersible heaters into environments. The heater cut-off is the longest sensor rod in the sensor head, and the control has four different outputs (and the most sensors of any other kit we offer).

Audio Alarms

Waterline Controls™ also offers audio water level alarms that can be wired into the Low Alarm, the High Alarm, or both. In all cases we use a Silencer Switch so the audible alarm can be silenced whenever necessary. These water level alarms are loud and used when an audible warning is needed for operator reaction or as a redundant warning in addition to BMS.

Contact Waterline Controls™

If you are looking for a low water alarm (perhaps a water tank low level alarm for a fire protection storage tank) or a high water level alarm system (maybe to use in connection with water well tank) we have a robust, accurate, quality solution for you. Our systems have an average life of 15 years, provide 99% accuracy, and are easy to install and integrate with your existing BMS. In addition, the sensors we use won’t plate, foul, or degrade and all parts come with a 5-year limited warranty.


All of our liquid level controls and liquid level sensors are assembled right here in the U.S.A.
where we monitor every step of the process.


We offer products comparable to the products offered by the above companies. See our website pages for further information on the products. The tradenames and trademarks in this page are owned by their respective companies or are the same name as the company. They are mentioned for comparison purposes only. They are in no way affiliated with System Dynamics, Inc or WaterLine Controls.