High Water / Sewer Bill Check all toilets and faucets. Running toilets and dripping faucets are the biggest cause of excessive water use. Toilets may be checked by placing a few drops of food coloring in the tank. Do not flush. If after 10 minutes the dye appears in the bowl, the toilet has a leak. Leaky toilets can usually be repaired inexpensively. Also check if the water level in the tank is too high and spills into the overflow tube. If you require an appointment, please call the Water Department office upon receipt of your bill. A continuing problem will affect your next bill if not repaired.