COOLING TOWER SEWER CREDIT WORKSHEET
Review your facility’s water bill. Notice that you are charged a fee to supply water to your facility as well as a fee to return the water to the city. Not all of the water used is returned to the sewer system. The city assumes that all the water that is supplied to your facility is returned. They base your sewer costs on the total amount that enters your facility via the water meter.

Monitoring the amount of water supplied to the amount returned may be effective in reducing your water costs. With cooling towers, evaporation of water is often more than 50% of the total amount used in that system. The following calculations will help you determine the amount of water that is evaporated from your system and the estimated sewer cost savings. The amount of sewer reduction will be determined through the use of a water meter attached to the make-up and bleed off of the cooling tower. The difference between the two should be logged and reported to the city to provide them with the evidence they require to reduce your sewer charges.

EVAPORATION CREDIT CALCULATIONS