If you choose the right electronic water level control system, it will be safe yet cost less to operate than a mechanical float system over the lifespan of the cooling tower.
As an illustration, if you replace the mechanical float in a
cooling tower every three years, at a cost of approximately $300 each, plus
installation, then over 25 years, you will have paid a total of $2,400 for
eight floats. Compare this to a total of less than $500 for a simple $20
replaceable component part every 10 years plus the cost of rebuilding the
solenoid valve every five years at a cost of $75 each. As this example
illustrates, the right electronic water level control system can save you
thousands of dollars versus mechanical floats over the expected life span of
the cooling tower.