Why are my wastewater charges calculated using AWC?

Unlike the water that comes into your home, water that leaves your home down the sink or toilet is unmetered. Because of variables like outdoor water use, the filling of swimming pools, etc., charging to treat solely by how much water comes in would be unfair.

To fairly charge for wastewater services, Wastewater utilities use Average Winter Consumption (AWC). Wastewater fees are often calculated based on AWC because it provides a more accurate estimate of a customer's wastewater production throughout the year. Here's why:

Water Usage Discrepancy

Water consumption in St. Helena tends to fluctuate significantly during different seasons. During the summer, water usage may increase due to activities like irrigation or outdoor water usage. By using the AWC, which is determined during the winter months when water usage is lower, it provides a more consistent and reliable proxy for calculating monthly wastewater fees year-round.

Outdoor Water Exclusion

The AWC helps exclude water consumption that is primarily used for outdoor purposes, such as watering lawns or filling pools, which does not contribute significantly to wastewater production. By using the winter months' consumption, when outdoor water usage is minimal, a more accurate representation of indoor water usage and wastewater production can be obtained.

Preventing Overcharging

If wastewater fees were calculated based on higher consumption periods like summer, customers could be charged more for wastewater services even though a considerable portion of the water used during that time does not actually contribute to wastewater production. Using AWC helps prevent overcharging and ensures a fairer assessment of wastewater fees.

Promoting Water Conservation

By using AWC as a basis for wastewater fees, it encourages water conservation year-round. Customers who consistently use water sparingly during the winter months will be rewarded with lower wastewater fees since their AWC will be lower, reinforcing the importance of conserving water.

Overall, using Average Winter Consumption for wastewater fee calculations provides a more equitable and accurate method for determining charges by focusing on indoor water usage and eliminating seasonal fluctuations and outdoor water consumption from the calculation.

In St. Helena, AWC is recalculated per property each April, and takes an average of your monthly water use from the prior winter months.

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1. Where does our water come from?
2. How are these services funded?
3. What is the current condition of our water infrastructure?
4. What infrastructure investment projects are planned?
5. How are water and wastewater rates set?
6. When will City Council decide whether to accept the Advisory Committee’s Recommendations?
7. Can you help me understand what volumetric charges mean?
8. Can you help me understand the idea behind tiered water rates?
9. Can you help me understand the idea behind tiered water rates?
10. Why are my wastewater charges calculated using AWC?