Wastewater is the water that leaves your home or business after it has been used. This includes water from sinks, showers, toilets, dishwashers, washing machines, and other household uses. Once it goes down the drain, wastewater travels through the sewer system to a treatment facility where it is cleaned before being safely returned to the environment.
Unlike drinking water, which is carefully treated and delivered to your home, wastewater must be collected and treated after use to protect public health, local waterways, and the environment.
How Wastewater Charges Are Calculated
Because wastewater leaving your home cannot be directly measured, most utilities estimate wastewater use based on the amount of water used inside the home.
At WTCPUA, wastewater charges are determined using a method called winter averaging.
Wastewater Averaging Months. 
Each year, the utility reviews water usage during the winter months, typically November through February. During this time, outdoor watering is usually minimal, so water use more accurately reflects indoor use such as showers, laundry, and dishwashing.
The average of your water usage during these months becomes your wastewater average for the year. That average is then used to calculate your monthly wastewater charges.
This approach helps ensure that customers are not charged wastewater fees for water used outdoors, such as irrigation or lawn watering.
Why Winter Averaging Matters
Reducing water use during the winter averaging period can help lower your wastewater bill for the entire year. Simple actions like fixing leaks, running full loads of laundry, and being mindful of water use during these months can make a meaningful difference.
How AMI Smart Meters Help
WTCPUA uses Advanced Metering Infrastructure (AMI) smart meters, which allow customers to track their water use more closely than ever before.
Through the customer portal, you can:
• Monitor daily water usage
• Detect possible leaks early
• Identify unusual spikes in water use
• Better understand how your usage may affect your wastewater average
This technology gives customers more control and transparency when managing their water use and utility costs.
What Should NOT Go Down the Drain
Your home plumbing and the wastewater system are designed to handle water and human waste only. Many common household items can cause clogs, backups, and costly damage to sewer systems.
Please avoid flushing or pouring the following items down drains or toilets:
• Grease, fats, and cooking oils
• “Flushable” wipes (they are not sewer safe)
• Paper towels or tissues
• Diapers or sanitary products
• Food scraps
• Chemicals, paints, or household cleaners
Keeping these materials out of the sewer system helps protect infrastructure, prevent backups, and keep treatment systems operating efficiently.
More Resources & Information:
FATS, OILS & GREASE (FOG) PROGRAM Commercial Customer Compliance Guide